Archaeologist needing help

mwillis

Hi, I am hoping someone here can help me.  I am an archaeologist and I have been using photogrammetry to record prehistoric petroglyphs (ancient carvings in stone).  Can you recommend any 3D enhancement techniques that might make these faint carving stand out in the 3D model? It doesn’t matter if the 3D model looks photo-realistic.  The most important thing is that the glyphs are visible even if they look a little funky or overly exaggerated.

Here is a screen shot showing an example of what the 3D data looks like:

 

I have had decent results from Radiance Scaling in MeshLab but it doesn’t create a texture I can use in an animation.

Here is what the Radiance Scaling looks like:

 

I’ve played around with Knald (which is awesome) but I’m not getting good results.  This may be just my inexperience with the software.

Here is a low polygon OBJ of data in the above screenshot:

https://www.dropbox.com/s/1500e516t61p749/sample.zip?dl=0

Any assistance would be hugely appreciated!

Mark

m4dcow

Interesting stuff. You could probably try overlaying a curvature map on the diffuse, this will highlight the edges and crevices. I just did a quick mock up in substance designer baked down to a piece of proxy geometry (the orientations were different, but you get the idea).

mwillis

Thanks M4dcow!  That is what I'm looking for.  Did you use xNormal to make the curvature map?

fatihG_

You can bake curvature in Knald as well.

However the default is set to dual channel, which means concavity gets stored in 1 channel and convexity gets stored in another channel of an image. Resulting in a green/red map. This is usefull if you want to tweak the edge highlighting separately from the cavities.

You can set the dual channel option to single channel as well, which mean you will get a map that you can set to overlay, like m4dcow did. 

m4dcow

mwillis said:

Thanks M4dcow!  That is what I'm looking for.  Did you use xNormal to make the curvature map?

I used substance designer myself, but as mentioned above many packages can generate a curvature map.

mwillis

Thanks faithG_ and m4dcow.  I really appreciate the help.

RN

Hi. Something I would also try is baking the displacement (heightmap) of that mesh, you usually get a greyscale texture from that.
Then it's a matter of photo enhancement: you can bring that texture to an image editor and use filters and adjustments to emphasise the brightness range that holds the details that you're after --with a Curves or Levels adjustment in Photoshop, for example.
Just make sure to export that heightmap as a 16 bits-per-channel image so there's no noticeable precision loss when you go process it.

At the end, you can use that modified texture back on something like a highly tesselated plane as a displacement map, if you need it to look 3D again.

cptSwing

Possibly helpful if you'd like to work on the geometry itself? Emulate Mudbox's Amplify Brush in Zbrush