Author Topic: Red Coloured MESH  (Read 209 times)

Andrés

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Red Coloured MESH
« on: January 22, 2018, 05:50:02 PM »
Hi There!

Recently i've scanned with structure sensor from an ipad and I can see it perfectly in Meshlab, but when I try to load it on Meshmixer it gives me a red mesh like the one that I have attached.

The file is a .obj with their respective .mtl and .jpg files. Im running the last version of Meshmixer 3.4

It has happened me before, but I can't understand why exactly happens.

Can somebody guide me on fixing this issue? i want to see the color because it is extremely important to our application.

Best Regards,

Andrés




MagWeb

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Re: Red Coloured MESH
« Reply #1 on: January 22, 2018, 06:33:42 PM »
Hopefully this doesn't mean that your mesh is non manifold all over....: What happens if you disable rendering of boundaries (> menu:View click on ShowBoundaries)?
I'm just a user as you are. Being no Autodesk employee: I do not know where this road will lead to, nor do I claim to've all stuff got right.

Andrés

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Re: Red Coloured MESH
« Reply #2 on: January 23, 2018, 02:32:38 PM »
Hi There MagWeb,

If I do What you ask just the blue lines disappear (see the attached red_1.JPG file)

I've managed to see the color image by moving it to a separate folder on the desktop (see the color.JPG file) any ideas why this does work?

Ok, but right now i have other problem .. when I apply "inspector" on the file, it is FULL of errors (see the inspector.JPG file), the scan comes directly from the structure sensor app for scanning, is there any way to fix this?  because if I use "repair all" from inspector i get like half the scan deleted.

Best Regards

Thank you!!

MagWeb

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Re: Red Coloured MESH
« Reply #3 on: January 24, 2018, 04:55:58 AM »
A textured obj needs a bundle of three files:
- OBJ
- MTL
- some image (as here e.g. JPG)

The OBJ links to the MTL and the MTL links to the JPG.
Now your files need to be on the location the link points to. Otherwise the texture can't be found by MM.
Now there are two cases:
1. The MTL isn't where the link in the OBJ points to >>> OBJ will be loaded ignoring a texture AND texture mapping >>> object will be "white" (which is "grey" actually using the MM's default shader)
2. The link between OBJ and MTL works BUT the JPG isn't where the link in the MTL points to >>> OBJ will be loaded keeping texture mapping BUT no JPG was found >>> MM's texture shaders will show the object in red (actually it replaces the not found texture with a all over red image). Obviously this is the issue you had.

If you run into such an red textured issue: Open the MTL in some text editor app to see where it expects the texture image (in most cases this is in the same directory where OBJ and MTL are).
Search for the line starting with "map_KD". E.g "map_Kd Example.jpg" expects the image Example.jpg to be in the same directory as the MTL while "map_Kd Something/Example.jpg" expects Example.jpg in a subdirectory(of MTLs directory) named "Something". You may edit the MTL or move the image to the expected location.
--------
Your second issue:

Seems your structure sensor app didn't construct the mesh properly.

You could reduce the SmallThresh slider > magenta pins will turn to blue or red pins.
But that does not solve your issue. Inspector will keep the particles now but close any open boundary individually which results in many small, but now watertight particles...It's a almost impossible task to Join the boundaries manually....

You might try EDIT/MakeSolid (if it works) but this will turn the texture to per vertex color (which might be not as good as the texture - depends on the output's vertex density). Maybe this is good enough for your needs?
Another thing you might do is to do a completely new surface reconstruction (as ball pivoting, marching cube or poisson) in some third party app (as in Meshlab/Filters/Remeshing-Simplification-SurfaceReconstruction).
Unfortunately something like this (except MakeSolid) doesn't exist in MM.
« Last Edit: January 24, 2018, 05:26:57 AM by MagWeb »
I'm just a user as you are. Being no Autodesk employee: I do not know where this road will lead to, nor do I claim to've all stuff got right.

MagWeb

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Re: Red Coloured MESH
« Reply #4 on: January 24, 2018, 09:15:21 AM »
Another maybe easier option:
To repair you might also try Netfab https://www.autodesk.com/products/netfabb/free-trial which offers a free 30 days trial for non commercial usage (after that period it is still functional but restricted to basic features).
I'm just a user as you are. Being no Autodesk employee: I do not know where this road will lead to, nor do I claim to've all stuff got right.