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Author Topic: Photoscan giving me (two) different alignment point clouds (Bug?)  (Read 22934 times)

Marcel

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Re: Photoscan giving me (two) different alignment point clouds (Bug?)
« Reply #15 on: March 28, 2015, 11:00:17 AM »
However what I did notice, even though achieving a much superior result is that my generated model is still quite noisy, my photos are well exposed and shot at the lowest ISO (160) and even the noise within the photos was cleaned up, I don't know what could be causing a bumpy mesh :(

A bumpy / noisy mesh could be because of blurry photos. Go through your photos and see if they are in focus at the pixel level. Remove photos that are completely out of focus or show camera shake, and re-align the whole set or use Tools->Optimize Cameras. Be very strict about photo quality.

Another issue can be when the shape of the object changes in photos (ie. your subject moved their head or changed expression). It's hard to keep perfectly still during the whole shoot.

If you use too much noise reduction you might remove the pixel detail that Photoscan uses for reconstruction, so be careful not to crank the noise reduction too high.

Even the super 100+ camera rigs can show some noise in harder to scan areas, so don't expect perfect output.



3D_Scan_Fan

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Re: Photoscan giving me (two) different alignment point clouds (Bug?)
« Reply #16 on: May 10, 2015, 04:15:08 AM »
Hey guys, so sorry for the late reply, but I have been playing around with many different things and have been getting pretty decent results.

I dont think anything can change the fact that the mesh is noisy, my still are all generally in focus and after carefully inspecting the photos with the noised cleaned up there was little-to-no detail loss (incase I could see abit more due to no noise interfering). I have instead taken the mesh into Geomagic studio where I decimated a 60-70million polymesh down to 12.5% which (as I've discovered the hard way) makes things alot more manageable.

With that mesh I applied a Free-form noise reduction with the smoothness set at the highest and I resulted in something that's pretty good but that needs alittle more work on.

My problem now is, how do I get the textures that was originally created in Photoscan to faithfully be mapped back onto the cleaned mesh? I have been watching that webinar over and over and over again during the part where he does applies the texture back onto his cleaned mesh but not in great detail, I'm just worried that the UVs of the original mesh might not match up exactly to the cleaned up mesh, nor do I know the workflow to this exactly because he mentions "Keep UVs (what does it do???)" but doesn't demonstrate it properly.

Can anyone help me here?

bigben

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Re: Photoscan giving me (two) different alignment point clouds (Bug?)
« Reply #17 on: May 10, 2015, 07:57:42 AM »
Import the mesh back into Photoscan and create a texture.  As long as you haven't scaled/transformed the mesh it should be fine.  The UVs are created at the time of mesh generation, although you could also UV map before importing and retain that mapping in Photoscan.

James

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Re: Photoscan giving me (two) different alignment point clouds (Bug?)
« Reply #18 on: May 11, 2015, 01:26:01 PM »
My problem now is, how do I get the textures that was originally created in Photoscan to faithfully be mapped back onto the cleaned mesh? I have been watching that webinar over and over and over again during the part where he does applies the texture back onto his cleaned mesh but not in great detail, I'm just worried that the UVs of the original mesh might not match up exactly to the cleaned up mesh, nor do I know the workflow to this exactly because he mentions "Keep UVs (what does it do???)" but doesn't demonstrate it properly.

You only have to worry about 'keep uv' if you have a UV layout that you particularly like. In the webinar i think he generated his own UV layout based on the retopologised mesh, which it makes sense to 'keep' as it has a much more logical layout than that auto generated by photoscan.

If you have no particular attachment to your uv layout, or don't have one at all then just stick with generic mapping and let photoscan generate a new one when you generate the texture again for the retopologised and reimported model. So long as you didn't translate, rotate or scale the model it should all be fine.

* edit - just noticed that's almost exactly what bigben said... and more concisely!
« Last Edit: May 11, 2015, 01:29:16 PM by James »

3D_Scan_Fan

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Re: Photoscan giving me (two) different alignment point clouds (Bug?)
« Reply #19 on: May 12, 2015, 12:45:52 AM »
Hmmm, that simple huh? :D

So all I do is just import mesh (which replaces the current one in the chunk, then just 'Build Texture' and that's it?

Also, how would I take it into Zbrush? It says that my (decimated and denoised) mesh contains no UVs and that I would need to apply UV mapping or polypaint. How do I get the texture that was generated in Photoscan onto the mesh in Zbrush?? :(

3D_Scan_Fan

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Re: Photoscan giving me (two) different alignment point clouds (Bug?)
« Reply #20 on: May 12, 2015, 02:16:57 PM »
Anyone?

Anyone at all may I ask?

James

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Re: Photoscan giving me (two) different alignment point clouds (Bug?)
« Reply #21 on: May 12, 2015, 03:11:52 PM »
I haven't used zbrush, so only guessing!

If you have 'decimated and denoised' in zbrush then presumably you will have lost the uv mapping that was originally generated when you first textured the mesh in photoscan.

To generate a new uv map, you will have to either:

1. import the 'decimated and denoised' mesh into photoscan and generate texture using generic mapping (this will generate a new generic uv map for your 'decimated and denoised' mesh
2. do some uv unwrapping of the 'decimated and denoised' mesh in zbrush
3. uv unwrap in some other software

If you do #2 or #3 then you still need to do #1 but using 'keep uv' instead of 'generic' mapping.

3D_Scan_Fan

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Re: Photoscan giving me (two) different alignment point clouds (Bug?)
« Reply #22 on: May 12, 2015, 07:49:44 PM »
Well what I've been doing was importing yhe decimated-denoised mesh into Photoscan, building a texture map for it and exporting an FBX file from Photoscan including a texture being made through it. Then i would take it into 3ds max which actually opens up the mesh with the texture in place correctly, then I would export that into an OBJ keeping yhe texture coordinates during the export, finally that exported OBJ containing UVs is imported into Zbrush and when i start applying a texture map it works, but not as it should be, it looks completely patchy and messy, reading it all wrong :(

And it's really strange, the mesh isnt that heavy but everytime i try adding a UVW Unwrap modifier to the mesh in 3ds max is seriously has a very hard time doing so, keep freezing, unresponsive and somewhat slow. I just thought i could redo the seams there and export a new texture based on that before doing any changes to it in Zbrush.

So I suppose what you're saying is, import the decimated-denoised mesh into Photoscan and build a texture using 'Keep UVs'? But wouldn't the outcome be different from 'Generic' or if one was to use any other option?

Also how would this differ? The mesh would still be the same and tbe exported texture map looks the same too (from my recollection).

mrb

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Re: Photoscan giving me (two) different alignment point clouds (Bug?)
« Reply #23 on: May 12, 2015, 09:15:57 PM »
You need to use the "flip-v" button on the texture in ZBrush.  Textures come into ZBrush upside down by default.  Same when you export a texture FROM zbrush - you need to flip-v it.

3D_Scan_Fan

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Re: Photoscan giving me (two) different alignment point clouds (Bug?)
« Reply #24 on: May 14, 2015, 01:29:30 PM »
Okay wow, that was all what was needed to be done, feel abit stupid now :(

But in anycase, how would i go about doing it for 3ds max then??

3D_Scan_Fan

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Re: Photoscan giving me (two) different alignment point clouds (Bug?)
« Reply #25 on: May 17, 2015, 09:34:07 PM »
No? Anyone at all?

I haven't used zbrush, so only guessing!

If you have 'decimated and denoised' in zbrush then presumably you will have lost the uv mapping that was originally generated when you first textured the mesh in photoscan.

To generate a new uv map, you will have to either:

1. import the 'decimated and denoised' mesh into photoscan and generate texture using generic mapping (this will generate a new generic uv map for your 'decimated and denoised' mesh
2. do some uv unwrapping of the 'decimated and denoised' mesh in zbrush
3. uv unwrap in some other software

If you do #2 or #3 then you still need to do #1 but using 'keep uv' instead of 'generic' mapping.

Well I've taken that as one of my steps, I Dynamesh'ed the mesh in Zbrush quite low and exported it as an OBJ and imported it back to Photoscan however the placement of the model is completely off, the transform and rotation does not match the original/dense cloud at all.

Either way with that I proceeded with Building a Texture for it as you normally do and not surprisingly everything came out looking wrong, complete garbage :(

How would I go abouts doing this? Bringing a modified mesh in Zbrush into Photoscan to work with??