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mazoola
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Export/Import issues

Emmanuel -

I've been working on some custom object models for a client, some of which require editing of the model or material definitions, and I've found what seem to be a couple of problems with SH3D's object loader and/or object writer.

The first has to do with setting and maintaining illumination models. As I've been modeling primarily in Sketchup, which ignores most advanced texture attributes, I've settled on the following workflow:

1. Export Collada-format model from Sketchup
2. Import model into SH3D
3. Manually tweak materials to add shininess
4. Export object in Lightwave format
5. Edit object and material definitions
6. Import modified Lightwave model into SH3D

However, I've discovered during export of the OBJ model from SH3D, for materials with a shininess > 1.0, the application sets Ks and Ns correctly, but incorrectly sets the illumination model to 'illum 1'. If you then re-import the model back into SH3D, since the illumination model < 2, Ns is set to '1.0' and Ks set to '0.0 0.0 0.0'. To maintain the exported shininess settings, the illumination model has to be edited to read 'illum 2' for any material with Ns > 1.0.

(I haven't tested for materials with a illumination model > 2.0 -- for instance, for translucent materials -- to see if they maintain the correct model.)

A second issue I've found is that Ka does not appear to be used correctly during highest-quality renders, at least; however, I suspect this is a byproduct of the way SunFlow's uber shader works. I mention this in case my quick parse of the SunFlow source is mistaken, and Ka should have some effect in renders.

The easiest way to demonstrate is to edit a material file and set Ka to something like '0.0 0.9 0.0'. In the 3D window and Q1 and Q2 renders, objects with the modified material will display a marked green tint. When rendered at Q4, though, the ambient color is ignored.

As the workaround for the first issue isn't onerous, and the second issue emerged only during an intentionally unrealistic test, none of these should be considered urgent; however, you might want to address the export issue as part of your 5.3 release.

Thanks,
maz
[Jun 24, 2016 10:55:16 PM] Show Printable Version of Post    View Member Profile    Send Private Message [Link] Report threatening or abusive post: please login first  Go to top 
mazoola
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Re: Export/Import issues

Emmanuel -

As I mentioned elsewhere, in my extensive, 3.5-minute review of OBJWriter.java I couldn't find any obvious reason for the incorrect illumination model to be exported. Subsequently, though, I exported a model that included seven textures with some degree of shininess -- and one of the seven exported as 'illum 2.' (On my previous attempt with that model, prior to minor revisions, all of the seven exported as 'illum 1.') Just FYI; if there's anything I can do to help track this down, just ask.

Thanks,
maz
[Jun 25, 2016 4:10:52 PM] Show Printable Version of Post    View Member Profile    Send Private Message [Link] Report threatening or abusive post: please login first  Go to top 
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