Modeling Maynooth Castle Part 7 – The Final Product

The castle is finally complete! Since the last post, I’ve added some trees to the scene and cleaned up the last of the materials.  Unfortunately, exporting the scene into sketch fab is not quite as successful as the rendered version in the 3DS Max.  For some reason, the materials used on the roofs of the various buildings do not export and neither do the materials for the trees.  However, I think its important to be able to move the model around, so I’ve decided to include the sketch fab version, even though it only looks partially complete.

The Real Final Product

The real product looks pretty good when rendered in 3DS Max.  I’ve included a number of screenshots from the rendered version below.  Hopefully, these will give you an idea of what the final product looks like in 3DS Max.

Front of Castle

Front of Castle

East Side of Castle

East Side of Castle

Back of castle. Note shadows from sunlight (which is behind castle)

Back of castle. Note shadows from sunlight (which is behind castle)

West side of castle

West side of castle

The Sketch Fab Version

Below is the version that exported to sketch fab. While this is the more “interactive” model, sadly the export process from 3DS Max doesn’t seem to play well with textures that are embedded in 3DS Max. So you can see that both the trees and the roofs of the buildings (both of which are 3DS Max built-in materials as opposed to custom materials) don’t export into sketch fab. This is unfortunately because it doesn’t give the full picture of the model, but this version does give you something to play around with.

UPDATE

I tried adding custom materials to the roofs and the foundation of the keep outset building in order to get those to render. While I don’t like the final output in 3DS Max as much as the original (and thus for the sake of the project, I’m keeping the original in tact), it does look a little bit better in sketch fab since those areas now have exported materials. I’ve included this new sketch fab version below.

Modeling Maynooth Castle Part 4 – Materials & Lighting

Since my last post about Modeling Maynooth Castle, my progress has been solid but largely uneventful.  I haven’t encountered any major issues or problems outside of the normal day to day frustrations of modeling, such as paying extra attention to that one polygon that doesn’t seem to want to be shaped the right way or fixing an accidental extrusion, etc.

After making significant progress on the model itself, I decided to start applying some materials and lighting.  The lighting itself was relatively simple.  Since I’m dealing with a castle that was destroyed in the mid 16th century, I decided I was only going to use natural light.  Thus I was able to easily implement a daylight system.  While I couldn’t quite set the date of the daylight system to 1534 (the year the castle was destroyed), I was able to take it back all the way to 1583, which is the farthest back the software would calculate. I set the time of day as noon and set the appropriate latitude and longitude in order to calculate the position of the sun.  3DS Max made all of this very simplistic, and I had no issues implementing the system.

The materials have proven to be a bit trickier.  I took pictures of the current keep walls, as I hoped to use those as materials.  I pulled one of these pictures into photoshop and used the patch tool to create a seamless, tileable texture.  I think applied this texture as both a bump map and a diffuse map to a material and mapped the material to the keep.  The results are below:

keep_material1

The result isn’t bad, but I don’t feel it’s anywhere near complete. I started experimenting by applying a UVW map.  Then I decided to scrap the original material and create a multi-sub-object material that would allow me to set different materials for different areas (such as the roof, the wood paneling that is part of the roof, etc).  I also decided to create blends and use the images of the castle walls as maps for the blend.  The result ended up with the castle walls themselves looking a little cleaner:

keep_material_multiobj

I think the walls of the castle itself look a little better (ignore the giant cross shape in the middle for now.  Those are actually separate objects I haven’t applied the new material to yet).  However, I don’t think the multi-subobject approach is going to work for the roof:

keep_material1_badroof

 

As you can see, not only does the material not look different (it should have more of a tiled slate look rather than stone) but you can also see each distinct polygon where the material was applied.  I think I’m going to have to trash the roof and rebuild it so it is a separate object that I can apply its own material to.

I’m going to continue working on it to see how I can improve upon it.

Modeling Maynooth Castle Part 3 – The Keep

I started modeling the keep a few days ago and felt I was making good progress.  Unfortunately, I was wrong.  However, I’ve learned a very important lesson:  when doing extrusions on an object, always zoom out to make sure you didn’t accidentally destroy the geometry.  Sadly, this lesson cost me about 3 hours’ worth of work.  Thankfully, I started making regular backups of my saves; otherwise this could have been much worse.

The Process

I started the keep with just a standard cube. I then constructed small towers that went along the tops, and for the crenellations, I did what I have always done—I extruded the polygons of the cube (after converting the cube to an editable polygon). I’ve never had a problem with this. Here is what the top part of the keep (which was the area I was focused on) looked like when I noticed my problem.
Top of Keep
I then zoomed out in order to inspect some aspects of the roof of the keep (for which I was about to create the pitched roof). That’s when I noticed my problem.
Messed Up Keep
As you can see from the photo, quite a bit of the geometry of the keep is distorted. Random sections are extruded or missing. The bottom of the keep was completely distorted. I probably could have fixed it, but I decided the amount of work it would have taken me to fix it most likely would have equaled the amount of time I spent getting to that point since my last back up. So I decided to cut my losses and simply revert to my last backup.

What Went Wrong?

I’m not entirely sure where everything went wrong, to be honest. The only thing I can suspect is that I accidentally selected other polygons while I was selecting the polygons for the roof (either that or I had failed to set the height segments when converting to an editable polygon and thus was extruding the entire height of the keep as opposed to one that was supposed to be closer to 1m3.

Lessons Learned

One lesson I’m taking away from this is to always check my line segments before converting to an editable polygon, and another is to frequently check the entire object when making modifications which affect the geometry. But the most important lesson here is to create FREQUENT backups of my scene. Thankfully, this really saved me this time (as I only lost a few hours’ worth of work), so it’s definitely a lesson I have taken (and am continuing to take) to heart.

Modeling Maynooth Castle Part 2 – Crafting the Walls

In my first blog on modeling Maynooth Castle, I discussed the goal of my final project for AFF621 and a little bit of the background regarding the castle itself.  As I began the process of modeling the castle, I decided the first place to start would be to model the walls, which is what I intend to discuss today.  However, before I get started, I’d like to take a few moments to discuss the planning of the model itself.

A Little Project Planning

Like some graphic design software, such as Adobe Photoshop, 3DS Max requires you to think through how the model is going to be constructed, so that you can be organise your scene.  In order to start this process, I started thinking about what kind of objects would be in my scene, and how I wanted to arrange them.  I came up with the following major items that would need to be a part of the scene:

  • the castle walls
  • the keep
  • the church
  • the gates
  • the living quarters / kitchens / etc.
  • miscellaneous buildings (such as the stables, barn, etc.)
  • the river(s)
  • misceallaneous nature (trees, grass, any other surrounding items, etc.)

Depending on how quickly I am able to execute on the model itself, I may or may not be able to complete everything, so I’ve decided to prioritise the first 5 items with the hope of adding the other objects should I have the bandwidth.

In order to facilitate this process, I decided I would keep each of the above mentioned-sections in their own layers.  This way I could easy turn off entire sections if needed (which could be helpful while fine-tuning other aspects of the scene). Additionally, by grouping them in layers, I can focus on each section at a time—very similar to how I would construct a physical model from legos or other building material(s). With these decisions made, I decided it was time to start the actual modeling process.

Constructing the Walls

I decided to start with the walls for two reasons:

  1. They would form the boundaries of the rest of the inner buildings of the castle itself
  2. They would most likely be the easiest thing to model

I decided to do a quick Google search to begin with just to see if anyone had modeled anything similar in 3DS Max and might therefore have some insight into the process of building walls.  I was lucky enough to happen upon a video that discussed how to construct a castle using 3DS Max.  I watched some of it and decided that it may be useful later, so I’ve filed it away for future use. I also found a script that was created to make the construction of walls easier.  I thought this might be the ideal script to facilitate the creation of walls, so I downloaded it and started using it in my scene.

Unfortunately, the script wasn’t quite what I was looking for.  It’s the kind of script that is great for creating brick walls, but one of the biggest problems I had is that, while it allowed me to set the number of segments for length and height, I couldn’t set the number of segments on the width.  Since I needed to create crenulations along the top of the walls, using this script would have meant manually creating individual crenulations as opposed to using some effects on the wall itself.  I also discovered the script was very computationally intensive and a single wall greatly reduced the processing power of my laptop.  Ultimately, I decided to discard the script and create my own walls from scratch.

I decided to start by creating a box that met the dimensions of the wall I was trying to construct.  I then gave the wall an appropriate number of segments for length, width, and height that would simulate brick work. For example, the south wall is 86.8 metres long, 3.51 metres wide, and 4.96 metres tall. As a result, I gave it 86 length segments, 3 width segments, and 5 height segments which makes each stone roughly 1 metre x 1 metre x 1 metre.  This was an arbitrary decision but one I felt was reasonable.

After drawing out the wall, I converted it to an editable polygon and then used the extrude tool to create crenulations along the top.  I decided each crenulation would be roughly 2 polygons wide and 1 polygon deep, and would be extruded by 1.016 metres.  I then built the remaining 3 walls following the same pattern.  When I was finished, the scene looked as below.  Note: each wall is color coded so I can easily keep track of what wall it is.  The south wall is red; the east wall is yellow; the north wall is green, and the west wall is blue.

Walls_Start

Next, I needed to fit the walls together.  The castle walls themselves do not form a perfect square, but rather bend at some points to create a sort of rounded, circular square.  There are also some breaks in the walls where the walls either protrude or where the walls are broken up by gates or other buildings. I accomplished this in a number of ways: by creating generalised boxes of the appropriate size as placeholders, by cutting up the walls to create the protrusions, and by using soft selection to bend sections of the walls. The outcome can be seen below.

Walls_Connect

As you can see, there was a drastic change in the state of the walls from their first construction.  It’s slowly starting to come together.

Further Struggles

One of the things I’ve struggled with a bit is the application of materials. I have some images of the castle walls themselves. I was hoping to apply them as both a bump map and a diffuse map to create the illusion of stone on the walls.  Unfortunately, it hasn’t worked so well.  Either the images tile too much and look fake, or they blur and, well, look fake.  This will be something I’ll have to work on more later.  I’m sure I’ll blog about it in future posts.

Next Steps

Next, I’m going to focus in on the castle keep and the enclosing walls. Hopefully this will be a little easier than the outer walls, especially now that I’ve picked up a few tips and tricks. More to come later . . .

Modeling Maynooth Castle Part 1

For my final project for AFF621 – Remaking the Physical, I was tasked with creating a 3D model of a cultural heritage object.  After considerable deliberation, I selected Maynooth Castle, which is a castle that once stood in the heart of Maynooth and was a major seat of power in Ireland from its construction in the latter part of the 12th century until its seige and destruction in 1534.  I selected it for two primary reasons: my love of ruined castles and the lack of information showing what the castle likely looked like during the height of its power, prior to its destruction.

Over the course of several blogs, I will recount the steps I have taken to produce the model and what trials and tribulations I have endured.  This is my first forray into creating 3D models, and while I’m excited to see the final output, I must admit to some trepidation regarding the scope and ambition of my project.  But I have always risen to a challenge, and this time is no different.  Hopefully, my efforts will be met with success, and by documenting my process and trials as I go, hopefully not only will I learn something from the experience, but so, too, will my readers.

Researching the Castle

The castle itself was originally built in the latter part of the 11th century and was a seat of power for the Fitzgerald family.  While I will save much of the formal history of the castle for my official report, I will note that the castle stood as a whole for nearly 300 years.  It fell in 1534 after a 10-day seige by the British, thanks to the rebellion of Thomas Fitzgerald, 10th Earl of Kildare.  While the castle was restored in 1630, it was destroyed again in the 1640s during the Irish Confederate Wars.  Since then, the castle has remained in ruins and is now run as a cultural heritage site by the State. It is open during the summer months for tours.

Unfortunately, due to the age of the castle, not much information remains regarding what it may have looked like during the height of its power, so most of my model is based on speculation of architects and other historians much more qualified than I.  I will be building my model based on their work, and my report will detail those sources in depth.

Some of the information I received was from some older documents stored in the special collections area of the Maynooth University library.  These included a map of County Kildare (which had a lovely write-up regarding the history of the castle), as well as some hand-drawn images of the castle ruins at the time of publication in 1783.  Additionally, the library was also able to provide me with a development plan that was created for the Office of Public Works in the mid 1990s that included some architectural plans that were drawn up during the castle’s first reconstruction in 1630. Additionally, this document also contained some speculation from the architects creating the development plan as to what the castle may have looked like in the 15th-16th century prior to its fall.

Looking at the Models

Another source of information was the model housed within the castle.  When Maynooth Castle was converted into a cultural heritage site, a scale replica of what the castle likely looked like was created.  This scale model is housed within the keep (which serves as a type of museum for the castle itself).  Catherine O’Connor, the supervisor of the site, was gracious enough to provide me with early access to the castle keep (which is currently closed for the season) so that I could photograph the model and take measurements of each of the buildings.  This will allow me to construct my 3D model as accurately to this model as possible.  Ms. O’Connor was also able to provide me with some additional documents that detailed an archeaological excavation of Maynooth Castle that was conducted in June of 2000. Finally, Ms. O’Connor also provided me with contact information for one of the architects who worked on the development plan.  I will be reaching out to him over the next few days in hopes that he can provide me with any further information that may be of use.

Next Steps

The next thing I will begin tackling is the creation of the model itself.  I will likely begin by trying to create the outer walls, as well as the keep.  I will be doing this from the ground up in 3DS Max.  My next post will be written after I have begun tackling some of these aspects and will detail what struggles (and hopefully triumphs) have resulted from this endeavour. Stay tuned . . .

Explorations in Photogrammetry – Part 4

For part 4 of my series on photogrammetry, I will discuss the creation of a 3D model of the sepulchre, the object I’ve chosen for the second part of my 3D recording assignment (for more information regarding the sepulchre and the process of taking photos of the sepulchre itself, see Explorations in Photogrammetry – Part 3). As with the bowl from the National Museum of Ireland (see Part 1 and Part 2 of Explorations in Photogrammetry), the construction of the object utilised Agisoft’s Photoscan Pro and the use of Adobe Photoshop.

Creating the 3D Model

The process of editing the pictures in photoshop was no different than it was for the bowl from the National Museum. As I covered this in Part 2 of my blog series, I will simply refer you to that post for more information regarding the Photoshop process.

The creation of the 3D model in Photoscan was somewhat different this time.  The initial process was still the same as it was for the bowl.  I imported the 178 photos into Photoscan and used the programme’s image quality assessment tool to determine the quality of the images.  To my surprise, I found the quality of the images to be considerably higher:

Number of Images Quality % of Total
4 .50 – .59 2%
174 .60 and above 98%

However, I knew from my experiences while taking the photos that there would be some photos that would need to be manually filtered out.  These were primarily photos were the sun was at the wrong angle and caused bright spots to appear in the photo or where the the photos were so bright as to look overexposed.  This led to a further 37 images being filtered out of the result set.

I then began to apply a mask to each photo.  However, this process proved to be much more involved than with the bowl. When applying the mask to the photos of the bowl,  I was able to use the magic wand tool to select the background (which was a uniform colour), and with a few simple clicks—and a reasonably high success rate—filter out everything but the bowl object itself. The photos of the sepulchre proved much more difficult.

Due to the lack of uniformity in the background (which contained grass, trees, and other objects in the cemetery), I was unable to utilise the magic wand tool. Thus, I found I had to draw the mask around each view of the sepulchre in every picture individually, using the lasso tool. This was not only time consuming but oftentimes difficult to do precisely, as objects from the background would occasionally blend into the sepulchre, making it difficult to determine where the sepulchre began and other objects ended.

Once I finished the masking, I then began to run the images through the standard processing workflow in Photoscan Pro. For some reason, however, these images were taking much longer to process. While aligning the photos took about an hour and a half (which was to be expected), building the dense point cloud proved to be a challenge. I initially kicked off this process on my Sony Vaio. This is a relatively powerful laptop with 8GB of RAM, a dedicated video card, and an Intel i7 1.80GHz chip. After running for almost 40 hours and being only 40% complete with the creation of the point cloud, I decided to cancel the operation and switch to my MacBook Pro, which has 16GB of RAM and a 2.3GHz Intel i7 chip. As of the writing of this post, the process to build the dense point cloud has been running for 17 hours and is approximately 50% complete.

When I saw the amount of time it was taking to process this model, I decided to try to utilise another method. Rather than applying a mask to every photo and then building the dense point cloud based on this mask, I decided to simply crop out areas of the photo that simply didn’t belong (such as a few photos where I managed to capture my book bag or another person visiting the cemetery). Then I simply aligned the photos utilising Photoscan Pro’s built-in alignment tool. From there I manually cut out the extraneous information the software pulled in and created a dense point cloud. I then continued to manually remove the points I did not wish the application to include in the final model (such as some of the surrounding objects). From there I was able to build a mesh and provide textures to create a model. This method was much less time consuming as I didn’t need to apply the individual mask to each photo. The time to process all of the photos to build the dense point cloud was about 20 hours—still a very intensive process but much better than the time it took to process the photos utilising the mask.

Assessment

Overall, I am very happy with the model itself.  It turned out rather well given the lighting conditions and difficulties I had with background objects and processing.  As learning outcomes, I would make note of the following:

  1. Try to take the pictures on an overcast day.  While this is not always within your realm of control, pictures taken when the sun is hidden behind a cloud tend to be easier to process, especially since they do not have shadows.
  2. Consider your environment.  One thing I did not take into consideration was the surrounding environment.  Had I thought of it, I might have taken some old sheets to drape over some of the surrounding objects.  This would have made applying the masks easier.
  3. Don’t always rely on the creation of masks.  For this object, I found the model that did not rely on masks but rather required me to manually edit the point cloud to be much easier to create. With this type of object, given the background items, I highly recommend this approach.

Final Model

As I mentioned earlier, the model utilising the mask approach is still processing. Once it finishes, I may post it here as an update. However, the model that I created without the use of masks turned out rather well. You can view it below.

Model Created Without the Use of Masks

Coming Up Next…

In my final post, I will discuss the process of 3D printing. I will evaluate available 3D printing services and discuss my chosen selection.

Explorations in Photogrammetry – Part 3

In part 3 of my photogrammetry series, I will discuss the second aspect of the photogrammetry assignment: using an outdoor object.  While the mechanics of this aspect of the assignment were similar to that of the first part (see Explorations in Photogrammetry – Part 1 and Part 2 for more information), this part of the assignment presented unique challenges.  As I mentioned in earlier posts, while working at the National Museum of Ireland, I was working in a controlled environment.  The object was small and placed on a rotating table.  The camera itself was on a stationary tripod. And most importantly, we utilised artificial light and a lightbox to ensure proper and consistent lighting.  I had none of these luxuries for the second aspect of this assignment.

For the second part of the assignment, I was tasked with creating a 3D model, with the subject of the model being something outdoors—the challenge being the lack of a controlled environment, especially in regards to lighting conditions.  I chose a sepulchre as my subject, one of the many objects in the cemetery behind St. Patrick’s College on South Campus here at Maynooth University.  The cemetery itself is rather small and houses mainly priests and nuns who have served St. Patrick’s College (although supposedly there are 2 unmarked graves of students who took their own lives and whose deaths have entered into folklore regarding the “Ghost Room” on campus[1]). The cemetery has a number of interesting markers, sepulchres and a crypt. The sepulchre I chose was that of Rev. Jacobi Hughes who, according to the inscription, served as Dean of St. Patrick’s College for 15 years. I found the sepulchre architecturally interesting with a number of interesting angles and faces, which is why I chose it as my subject piece.

Taking the Photos

The process of taking the photos of the object was rather different than it was for the photos taken at the National Museum.  First, I had to be very aware of any shadows being cast—not just of shadows cast by the object and any surrounding objects, but also of shadows cast by myself.  Too many shadows would make it difficult for the software to accurately compile a point cloud.

Ideally, it is considered best to take photos on a cloudy day.  Given I am in Ireland, one would think this wouldn’t be a difficult task; however it would seem the weather was not my friend, and the sun decided to shine high and bright the entire time I was attempting to take pictures.  This meant I had to be very careful with how I positioned myself while taking the pictures.  Due to the size of the object, I had to move around the object in order to capture it from all of the requisite angles (as opposed to the bowl at the National Museum which sat on a turntable that I could then rotate).  As such, I often found myself having to reposition the view finder on the camera and hold the camera at odd angles in order to ensure my shadow wouldn’t fall on the object as I attempted to capture it.

Another downside was the lack of a true preview.  While working with the camera at the National Museum, I was able to keep it connected to my laptop, where I could preview every picture and, if necessary, make constant adjustments to the settings.  This was not feasible with the sepulchre object, as I was moving around the object and could not keep the camera connected to my laptop.  I had to rely on the view finder on the camera itself for a preview—an option which isn’t ideal for truly examining an image upon capturing it.

I was able to apply some lessons learned from the National Museum, however.  In this instance, I used a much higher aperture setting (I kept the f-stop set at 22) and allowed the camera to adjust the ISO, so as to optimise this setting.  Overall, I feel these pictures were much sharper and of a higher quality than the pictures taken while at the National Museum.

Coming Up Next…

In part 4, I will explore the process of creating the 3D model of the sepulchre. Specifically, I will be discussing the differences between the construction of this model and that of the bowl model from part 2. I will also assess the quality of the model and what areas of improvement could have been made to create a better object.

References

[1] Sam. “The Ghost Room in Maynooth“. Come here to Me. 20 July 2012. Web. 3 April 2015.

Explorations in Photogrammetry – Part 2

In part 2 of my series on photogrammetry, I will discuss the process of creating the three-dimensional model of the bowl from the National Museum (for more information on the process of taking the images of the bowl—which I mentioned in my last post—see part 1 of Explorations in Photogrammetry).  The process itself involves the use of two pieces of software:  Adobe Photoshop and Agisoft Photoscan Pro.

Photoshop to the Rescue

The first step was to unify the images. This process was done using Photoshop and a few of its “auto” features. I began by setting up a batch job (learn how to create batch jobs in Photoshop here). This job applied the following auto corrections in order:

  1. Auto contrast – to adjust the brightness settings of each photograph and create a uniform brightness/contrast
  2. Auto colour – to correct any oddities in colour
  3. Auto tone – to smooth out an residual white / black in the image and apply a universal look

Each file was then re-saved in a separate location. It’s best practice to always keep a copy of the original image, unedited.

Building the Model in Photoscan Pro

The next step was to import the photos into Photoscan Pro.  Photoscan Pro is software that allows a number of images to be “stitched” together using a point cloud.  This point cloud is then used to construct a 3D model of the object.

The first step involved assessing the quality of the images.  Photoscan Pro has a built-in quality assessment tool.  After running this tool against all the images imported into the programme, each photo is then given a score (from 0 to 1) that shows how high the quality of the image is in order to align it and produce a 3D model.  While learning how to use the software in class, we were taught a general rule of thumb is to only use images whose quality is .6 or higher.

After importing the images and assessing their quality, I received the following results:

Number of Images Quality % of Total
7 .40 – .49 5%
45 .50 – .59 29%
101 .60 and above 66%

I was a little dismayed that such a large number of my images (over 30%) were under the .60 threshold.  I decided to run two different models in order to compare the results.

I began by excluding all images under .60 quality. I applied a mask to each image so as to instruct Photoscan to ignore everything other than object (this involved basically “cropping” out the background and having Photoscan ignore anything but the bowl object—a very time intensive process but well worth the results).  I then used Photoscan to align the photos, build a point cloud, a dense point cloud, and then a mesh.  This created a somewhat reasonable 3D model of the bowl; however there were a number of errors in its rendering and the model itself looked incomplete.

In order to correct this issue, I attempted to rerun the model by including the 45 images that were marked with an image quality of .50 – .59.  When including these images, along with the original 101 images of .60 quality or better, I received a much stronger model. This model lacked the errors in its rendering that were present in the first model and looked more complete.  Upon close inspection, however, one can see the very bottom of the bowl looks as though it was “cut out”.  This is not a feature of the bowl itself, but rather a failure to capture images at a deep enough angle so as to capture the entire inside of the bowl.

As I began to closely inspect the second version of the bowl, I also noticed there was quite a bit of “noise” in the model (areas of the bowl that looked pixelated or out of place).  I attempted to reapply the masks on the objects by cropping the images further (thus excluding the very edges of the object in each photo).  However, this did not turn out well. My bowl ended up rather flat-looking, as though someone had collapsed the bowl upon itself.  I think took the original point cloud from the second model and began manually cleaning up the cloud by looking for areas of white (which were the background and thus not part of the bowl).  After manually removing these points, I rebuilt the mesh and texture and developed my final model.

Assessment

Overall, the bowl turned out better than I initially expected, especially given this was my first attempt at such an endeavour.  Given the opportunity to repeat the process under the same settings, I would make the following corrections:

  1. Adjust the aperture and ISO. For most of the images, I was using an F-stop of 8 and an ISO of 640.  I think I would adjust this to lower the ISO (thus reducing visual noise in the image) and raise the F-stop on the camera.  The exact values I would use are difficult to say, but I would most likely try to lower the ISO to somewhere between 100 and 200 and raise the F-stop up to at least 22.  This would give me a crisper image, especially in regards to depth of field, as well as the added benefit of removing a small amount of noise that exists in the image.
  2. Adjust the shutter speed.  I left the shutter speed on the automatic setting for this exercise, mainly because I didn’t think I would need to adjust it.  Given another opportunity, I might attempt to manually adjust this setting to see how it affects the quality of light in the image (many of images seemed a little dark, despite all of the artificial lighting present).
  3. Adjust the angle.  I would also take another round of photographs at a much steeper angle so as to completely capture the interior of the bowl.
  4. Take more time.  As I was the first student to begin taking pictures, I self-imposed pressure to complete my pictures quickly, so as to ensure my fellow classmates had ample time with the camera as well.  If I repeated this process again, I would be less conscious of time constraints and take more time in between photos to evaluate the quality of the image and adjust my settings as needed.

Final Models

In an effort to show off the difference between the two different models, I’ve included both below, as well as a version of the bowl that was sent to the 3D Printer (more on 3D printing in a future blog post). The first is the “bad” model that only included the images with a quality of .60 or higher. The second model includes images with a quality of .50 or higher. Also note the absence of part of the bottom of the bowl where I failed to take images at a deep enough angle to cover the entire bottom of the bowl.  The model used by the 3D printer does not have the hole in the bottom of the bowl as I used 3ds Max to fill in the mesh.

“Bad” Bowl
“Good” Bowl
“Printed” Bowl

Acknowledgements

Special thanks to the National Museum of Ireland and their Archaeology department for allowing us to photograph some of their objects. The pictures taken of the bowl featured in this post and my previous post were courtesy of National Museum of Ireland – Archaeology. All rights reserved.

Coming Up Next…

In part 3 of my series on photogrammetry, I will discuss my choice for the second part of my assignment. I will detail why I chose the particular object in question and what challenges were presented to me as part of this aspect of the assignment. I will also detail the steps I took to overcome those challenges.

Explorations in Photogrammetry – Part 1

Our first assignment in AFF 621: Remaking the Physical involves photogrammetry.   Photogrammetry is a technique used to create three dimensional images of an object.  This is accomplished by taking a series of photographs of an object, where each photograph overlaps by at least 60%.  Special software is then used to create point clouds that “stitch” the pictures together into a three dimensional representation of the object.[1] 

Over a series of several blogs, I intend to document the process of photogrammetry used for my photogrammetry assignment.  The assignment itself calls for the creation of two different 3D models using photogrammetry. One of the models is to be a bowl housed at the National Museum of Ireland where the pictures can be taken in a controlled environment. The second model is to be one of my own choosing; however it must be taken in an outdoor setting where little environmental controls exist, thus giving us the opportunity to experiment with lighting, aperture, shutter speed, etc. The blogs will cover the following:

  • my trip to the National Museum of Ireland in Dublin
  • my choice of topic for the second model and the process involved in the actual photography
  • my experiences with the editing and creation of the actual models (2 separate posts)
  • an analysis of 3D printing and the service I would use to print my object

My Day at the Museum

For the first part of our assignment, we visited the National Museum of Ireland.  This was a fantastic opportunity to not only visit the museum, but to see some of the artefacts up close.  We spent the entire day in the museum photographing a number of bowls which dated from some time around 2,000 BCE. The Bronze Age era bowls themselves were largely used as drinking vessels and likely held some kind of beer.  Many of the bowls have a sun pattern on the bottom that some archaeologists speculate was tied to the worship of the sun by the indigenous people[2].

The process of photographing these objects was quite different than it was for photographing the second part of my assignment (the latter of which will be detailed in a future blog post).  As we were in a controlled environment, we were able to avail ourselves of a number of lighting techniques that wouldn’t be feasible outside such a setting.  One of these (which is also a personal favourite) was the lightbox.  lightbox The lightbox is white canvas-type cube that, as one of my classmates pointed out, looks much like a collapsible laundry basket. The object is then placed inside the lightbox and lights are placed around the outside.  The material of the lightbox acts as a sort of diffuser, softening the light and eliminating shadows. The image to the right shows the final setup of our lightbox.  The lights are positioned from all angles in order to provide the most light. This includes not only from the sides and front but also from above.  Once the object is placed on the turntable (which is positioned in the centre of the lightbox), the object can be slightly rotated in between each picture, allowing for the creation of the overlap between images necessary to produce an accurate model using photogrammetry.

Once everything is set up, the actual photography can begin.  As I mentioned above, the object is placed on the turntable within the lightbox, which allows the object to be easily rotated. Shane Using the EOS Utility (software provided by the Canon website, the manufacturer of the digital camera we used), we were able to preview each image on the laptop and adjust various settings as necessary.  Primarily I worked with the aperture (to define not only the light available but also clarity of the background and depth of field) as well as the ISO (which can allow for more brightness but must be used carefully so as not to introduce any visual “noise” into the image).  I decided to leave the shutter speed set to automatic, as adjusting this is more of an advanced technique and given the controlled environment, I didn’t feel it was necessary to adjust.  Once all of the adjustments were made, the process of photographing the images was quite simple.  Very few adjustments needed to be made in between images, and I was largely able to move from one image to the next with little intervention with the camera.

I decided to take images from four different angles, beginning at straight on, and then adjusting the angle of the camera up in order to capture further detail. The bowl was then flipped, and the process repeated in order to capture the bottom part of the bowl.  I was able to capture approximately 150 images in about 50 minutes (excluding the initial setup of the lightbox).

Acknowledgements

Special thanks to the National Museum of Ireland and their Archaeology department for allowing us to photograph some of their objects. The pictures taken of the bowl featured in this post and my previous post were courtesy of National Museum of Ireland – Archaeology. All rights reserved.

Coming Up Next…

In my next blog, I will discuss the outcome of these images, the steps taken to clean up the images for contrast, brightness, clarity, etc., and the process of utilising Photoscan Pro to create the 3D model.  I will also assess the quality of the images taken and what steps, if any, I would take in the future to ensure a higher quality of image as well as what lessons I can take away from this aspect of the assignment.

References

[1]US Bureau of Land management Publication: Tech Note 248 on Photogrammetry.

[2]Flanagan, Lauren. Ancient Ireland: Life Before the Celts. Gill & Macmillan, Ltd. 1998.