Body Object & VRay Issue

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Old 03 March 2013   #1
Body Object & VRay Issue

Hi guys,

we have hundreds of Body objects (originally .step files). And nearly all of them make very odd problems when using VRay. the material applied is rather simple. Dark greyish black diffuse color, glossy reflection and soe galvanized-like bitmap in the bump and the reflection channels.

If those are added, it gets very odd. It seems to have different scalings inside itself.

This Picture is just the Body Object. If we convert that to mesh/poly, reset xform smooth it and flip the normals, it looks better, but produces errors around the openings due to the horrible edgeflow etc.


In this image, we flipped the normals inside the Body object and added a procedural noise map for the bump reflection etc. (instead of a bitmap). As you can see, the scale is alike spread out over the surface, but it still looks odd.


And this is mental ray. Just flipped the normals of the body, applied an arch&design material with the same bitmap as in VRay, and voila, its the same scale all over the place.



Has anyone got any idea how to solve that? Apart from using mental ray? And even there: Anyone got any idea how to script the flip normals (if you use a normal modifier, it converts it into a flash and you get the errors around the holes again... so you need to flip them inside the body object - but doing that by hand would take ages)?

Any help is appreciated.
Btw: max 2013 &Vray 2

here one isolated body object: http://www.filedropper.com/testnetz
 
Old 03 March 2013   #2
I opened it and the normals are definitely jacked up. They were flipped, so I flipped them back. I also had to add an edit normals modifier, select all (ctrl + a), 'break' and 'reset' just to get it to render correctly. This is really weird stuff... xview>face orientation indicates that the normals are flipped, but they render fine. If you flip them to be correct, it doesn't render correctly until you break/reset the normals... ?

I'm using body objects w/ vray all the time, hardly ever have an issue like this. What app are they exporting .stp from?

Edit: For whatever it's worth, just converting to mesh and throwing on a noise renders fine, even if the normals are wonky.
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Chris L. Harkins

Last edited by Charkins : 03 March 2013 at 06:13 PM.
 
Old 03 March 2013   #3
Originally Posted by Charkins: I'm using body objects w/ vray all the time, hardly ever have an issue like this. What app are they exporting .stp from?

Just checked again. Its .IGS files, not .stp. Sorry for any confusion. By what I can make out they use Solid Works as software. Not entirely sure. It's just what it says when I ipen the IGS in a text-editor.

Originally Posted by Charkins: Edit: For whatever it's worth, just converting to mesh and throwing on a noise renders fine, even if the normals are wonky.


Converting to mesh sometimes related in errors around the holes because half of the vertices of the circle were connected to only one vertice on the opposing edge. Did any of that happen to yours?

We've been stuck on this for days now :(
 
Old 03 March 2013   #4
i often work with .stp and inventor files but to make sure not to have artifacts in animations and then correct the geometries and then re-render the whole thingie or parts of it i prefer to use the imported geometries as references and remodel everything
 
Old 03 March 2013   #5
Originally Posted by freeflow: i often work with .stp and inventor files but to make sure not to have artifacts in animations and then correct the geometries and then re-render the whole thingie or parts of it i prefer to use the imported geometries as references and remodel everything


Well, remodelling is not an option as it is far too much work to do And what's the point of importing CAD-data if you have to redo everything by hand?
 
Old 03 March 2013   #6
Try setting the Body Objects to render the viewport mesh. I wonder if it has something to do with the conversion at render time, and the difference between translation to mental ray and vray.

You can also try enabling the Weld and Smooth option.This removes the vertex normals and welds the vertices and instead uses Smoothing Groups (Face normals) to generate the mesh smoothing.

There could be a lot of things that could be the cause, but hard to diagnose without a file to look at.

-Eric
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Old 03 March 2013   #7
Originally Posted by PiXeL_MoNKeY: Try setting the Body Objects to render the viewport mesh. I wonder if it has something to do with the conversion at render time, and the difference between translation to mental ray and vray.

You can also try enabling the Weld and Smooth option.This removes the vertex normals and welds the vertices and instead uses Smoothing Groups (Face normals) to generate the mesh smoothing.

There could be a lot of things that could be the cause, but hard to diagnose without a file to look at.

-Eric



*ahem*

there is a file to look at
http://www.filedropper.com/testnetz

But I will try. i think the weld and smooth did help, but caused the edgeflow to go all crazy. I'll give the viewport-mesh thing a try later! Thanks!
 
Old 03 March 2013   #8
Oh yeah I did try that, but it is access is blocked here. Will have to try at night from home.

-Eric
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"The Evil Monkey hiding in your closet."
 
Old 03 March 2013   #9
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