Keyboard Photogrammetry

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snacksthecat
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13 Mar 2020, 00:10

SneakyRobb wrote:
12 Mar 2020, 14:22
Zbrush looks interesting. From my attempts there sometimes are little "hanger" pieces that are hard to remove. So that is cool and looks like it could help.

Also I like your scans of switches. I've been trying to figure out realitycapture for a few days. Not sure what I'm doing wrong but hopefully I can figure it out in the next 2 days, otherwise Ill post in the tutorial thread my issues.
Very cool. I like working in RealityCapture a lot. Whenever something turns out poorly in Metashape, that's my go-to. It produces really good looking meshes and textures. The only warning I have is don't get carried away with control points. I've spent hours upon hours carefully placing control points to help the app with alignment, to no avail. I've read people having success with them by setting very high weighting on each point (e.g. 200 vs. 10). But I myself just haven't been able to effectively use control points for alignment. If I put an hour of work in and the photos still don't align, I should just give up and move on.

I've recently figured out that you can do alignment in Metashape and export to .out (bundler) format. Then import the .out file into RealityCapture. But I'm not sure if the photos should be exported from Metashape as undistorted or not, and haven't had enough time to fiddle with it yet.

I also just got a digital drawing tablet so I can do touch-ups in Zbrush. So I guess you can call me snacksthedigitalartist now.

The next board I scanned is my indie SSK. So far its coming along really nicely but I'm also trying to test out different things to see how it effects the finished product. The main piece I'm adding to my workflow goes like this:
  • Run photogrammetry and generate mesh in Metashape
  • Export from Metashape, import to Zbrush, clean up bumpiness, holes, etc.
  • Remesh, unwrap, export from Zbrush. Import back into Metashape
  • Decimate down to ~250,000 faces
  • Run "Refine Mesh" tool (high settings)
When running "Refine Mesh", a few things to point out. First, I'm decimating down to a lower poly count because this procedure subdivides the mesh 3 or 4 times so if you don't do this, you end up with an insane number of faces. I'm also running it on "High" rather than "Ultra High" because apparently my PC doesn't have enough video memory for ultra. But that's probably okay because, lastly, I'm disabling all photos except for the ~150 closeup photos I took.

I'll go into detail more later but recently I've found I can really improve the quality of the mesh by taking one set of photos with the whole object in frame, mostly to capture the general structure. Then I come in with a zoomier lens and take some closeup pictures. The pictures from set #1 get the full shape of the object and provide a reference point for getting the camera positions from set #2.

It's a bit of a hassle because you end up taking a ton of photos this way. I'd also like to experiment with markers (like matt3o suggested in the tutorial thread). It might make my life a whole lot easier aligning the "general shape" set of images.

Oh and I've learned one more thing. I've been generating my meshes with way too many target faces. I basically have been allowing it to produce as many faces as needed. I've found that by reducing the target face count (something around like 750,000 - 1,000,000), I get a much prettier model. Fewer craters, bumpiness, etc.

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snacksthecat
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13 Mar 2020, 02:22

And it's done! I think I've taken this one as far as I can go with it, without taking more pictures. This one I wish the I'd set my white balance correctly (had it leftover from a different set). So it turned out a little bit green/yellow. I adjusted the sketchfab settings to compensate for this. Already went into some detail about what I've done differently these past few scans so not much more to say.

https://skfb.ly/6QSTH
Image

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SneakyRobb
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13 Mar 2020, 22:24

snacksthecat wrote:
13 Mar 2020, 02:22
And it's done! I think I've taken this one as far as I can go with it, without taking more pictures. This one I wish the I'd set my white balance correctly (had it leftover from a different set). So it turned out a little bit green/yellow. I adjusted the sketchfab settings to compensate for this. Already went into some detail about what I've done differently these past few scans so not much more to say.

https://skfb.ly/6QSTH
Image
Hi, that is a gorgeous model!

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snacksthecat
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13 Mar 2020, 23:20

SneakyRobb wrote:
13 Mar 2020, 22:24
Hi, that is a gorgeous model!
Thank you! Of course I see everything wrong with it but I've been staring at it for the past few days, after all.

I wanted to mention two things...

First, I'm totally sold on Zbrush. It's amazing what you can do in there in terms of manually fixing defects. I think this is exactly the tool I need to bridge the gap that my photos are falling short on. I've had so much fun with the program in the past week week that I decided to buy a drawing tablet thing. It was relatively inexpensive (I just needed something basic) and will give you more control in Zbrush (e.g. control over pressure). Haven't tried it out yet but I'm ready and excited to flex my nonexistent art skills.

Next thing, I got an ad for a kickstarter product; some sort of thing you attach to your camera to do focus stacking. I wasn't aware what this is but it sounds very cool. For those of you into photography, you almost certainly already know about this. But for those who are not, focus stacking is where the camera takes the same picture multiple times changing the focus each time. With the end goal of getting the entirety of what you're photographing in focus. You can imagine how this would be useful in photogrammetry. If my explanation didn't make sense, it will be more evident in this example from the-digital-picture.com website:

Focus StackedStandard
ImageImage

Well I'd gotten a new camera over the holidays. Seeing that kickstarter thing made me think this is some super premium feature/technique. I never imagined that my new camera (Canon RP) actually has this feature built in (which is surprising because it lacks some other things I wish it had). So I'm looking forward to trying it out this weekend. No idea how/if it will effect the software's ability to calibrate images but we shall see.

For anyone who is interested, sketchfab and RealityCapture are running a challenge/contest right now. The contest is to scan your favorite toy using the RealityCapture software, then upload it to the sketchfab website. RealityCapture is pay-per-input, so the software itself is free. Since it costs money to purchase input licenses, they're providing entrants with 20EUR of credits to use for the challenge. The contest runs through March and I'm probably going to try to scan something to enter this weekend.

https://sketchfab.com/blogs/community/s ... orite-toy/

I know, I know, "dear diary" right?

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SneakyRobb
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17 Mar 2020, 00:21

Interesting contest. I have some time at home right now. I might try this on my Optimus Prime or Tallgeese models

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snacksthecat
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17 Mar 2020, 03:25

Those would be cool to see!

One additional thing that might be helpful are the coded markers:
https://support.capturingreality.com/hc ... l-version-

They're little barcode-like things that get automatically detected in the images they appear in. The software creates a control point for each of the markers. I'm not sure if it is more effective than manual placement of control points but I wanted to try it out. I don't use this software enough to be able to know if there's a difference, sorry to say.

I'm trying to scan this wifi camera car thing. It's full of pitfalls but it will look so cool if it all comes together.

Image

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SneakyRobb
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18 Mar 2020, 15:28

Hi. That makes sense and is cool. I know you said that the narrow border areas can be a bit of an issue sometimes, so such markers make sense.

Does this robot device save times in terms of manually turning? Were you using a "lazy susan" sort of thing before where you would manually turn it by hand?


Also this is the dental scanner that my dentist used I think. Pretty fast machine actually, but that is to be expected when it costs tens of thousands of dollars.

https://www.youtube.com/watch?v=a40pLVe3pVY

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SneakyRobb
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20 Mar 2020, 20:08

Hi,

So I printed some miniatures I was going to send to snacksthecat, but they are at my parents house. They are self isolating with no symptoms. To be on the safeside I will wait for them to hopefully come out of the 14 days symptom free.

I wont send the models until that time. They do exist though and with some sanding/painting I think they would look really cool!

miniatures.jpg
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