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PostPosted: Tue Feb 12, 2008 2:05 pm 
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Location: Nottingham, UK
Hi, this problem is driving me crazy! I've been trying to track it down for about 2 hours now; modelling, remodelling, etc.

I seem to have a mysterious hole in my geometry that is letting light in but as you can seen from the image below, the sunlight (the only light source) seems to be travelling in a different direction for this hole!

All caustics are turned off but all object are in the same diffuse material so there should be no caustics anyway.

The geometry is 'watertight' (apart from the windows!) and I have attached and reattached vertices just to make sure. Model is very simple, single sheet polygons.

Does anyone have any idea about what is going on?

Modelled in XSI - I can email the file over if it'd help.

TIA.

Image

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Last edited by oz42 on Mon Jul 21, 2008 3:01 pm, edited 1 time in total.

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PostPosted: Tue Feb 12, 2008 3:12 pm 
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If you could email me the XSI scene, that would be great. Strange that it's also another direction than the sunlight.....

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PostPosted: Tue Feb 12, 2008 5:20 pm 
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The problem was the walls object, I saw it had some modeling history, but even freezing it didn't solve the problem. So I just triangulated it before sending the scene to Maxwell and it renders ok. I'm not sure why this is because if I don't triangulate first and just open the mxs in Studio, the triangles appear the same as if I had first triangulated it in XSI before export. Must be some tiny differences in the triangulation which causes this...

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PostPosted: Tue Feb 12, 2008 5:55 pm 
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WOW! Just tried it and simply triangulating the mesh solves the problem.

Thanks for this. I've never encountered this sort of triangulation issue before - weird!

This is definately one trick to keep in mind for later...

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PostPosted: Tue Feb 12, 2008 7:42 pm 
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What happens if you remove the glass in the windows and the object in the corner? Or are the windows just holes at the moment?

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PostPosted: Tue Feb 12, 2008 8:12 pm 
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The windows are just holes (there is glass but it's hidden at the moment).
Mihai's trick of triangulating the geometry has worked but it's strange that this has to be done?
I've been modelling another floor of the building today and, again, I've had to triangulate the walls to avoid light leaks!

Thinking about it...
Way back when, before XSI had a plugin, I used to export to obj and import that into Maxwell Studio. I had to triangulate before exporting from XSI otherwise there would be no geometry read from the obj file.
As soon as the XSI plugin came along this process was redundant and I have been using the plugin sucessfully for several projects.
Most of my projects are interiors and I always model the walls as single sheet, simple polyon meshes (untriangulated).
Has there been a significant change in the latest XSI plugin update that has altered the way that geometry is exported?
Just a thought?

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PostPosted: Wed Feb 13, 2008 9:19 am 
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oz42 wrote:
Most of my projects are interiors and I always model the walls as single sheet, simple polyon meshes (untriangulated).
Has there been a significant change in the latest XSI plugin update that has altered the way that geometry is exported?
Just a thought?


In fact, simple polygons are always 2 triangles, don't know for XSI, but in 3dsmax, we can display them

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PostPosted: Wed Feb 13, 2008 11:34 am 
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def4d; thanks. I know that all polygons are ultimately tri's but it just makes for a very complicated scene (visually) if they are all visable. Usually Maxwell can deal with XSI's geometry and triangulates on the fly whilst exporting.

The issue here is that there seem to be a discontinuity between where the triangle exactly are in XSI's untriangulated geometry and where the mxs file thinks they are (hence the holes, leading to light leaks) and so for this project I have to triangulate the geometry manually before exporting to Maxwell.

It's weird, I've never had to do it before, even with more complex geometry. I just wondered if it was a change in the way the latest XSI plugin (1.6.5) exports geometry?

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PostPosted: Wed Feb 13, 2008 4:28 pm 
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It seems just that particular geometry has something weird in it because the other parts didn't cause any light leaks. I'll export the walls object from Studio and import it into XSI to check with the triangulation inside XSI.

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