radiosity makes objects invisible?

Blender's renderer and external renderer export

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radiosity makes objects invisible?

Post by lastfuture » Thu Mar 20, 2003 10:19 pm


i've discovered blender a few weeks ago and have been very satisfied with the features of this great program. even as a former 3ds max user. now somehow i have run into a problem with radiosity during a test render.

the progress in getting to this problem:

1. made a box for a room.
2. made a lamp and gave the lamp shade and an faced, subdevided circle self illumination.
3. imported a small test desk with pc screen and chair made entirely from boxes.
4. selected all meshes with the A key and let blender calculate the radiosity shadow map
5. replaced meshes and rendered

the problem with the render can be seen in this image (look at the chair):

this is the version saved right before calculating radiosity (i only added a light so you can see the scene):

where did the 3 missing boxes of the chair go in the radiosity render? they are still visible in the viewport and i didn't change any settings regarding their tracability or alpha... or anything else.

i hope you can help me with this strange phenomenon

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Post by Jamesk » Fri Mar 21, 2003 10:13 am

First of all - questions concerning HOW TO USE Blender as it is really should be posted in the Q&A-forum at Elysiun - - but since you're here now:::...

This problem is usually caused by the fact that your final mesh, the radio solution, gets too many material indices. Currently there is no support for more than 16 different materials per mesh, and there are chances that this limit gets exceeded while the radio solver builds its final mesh.

The solution is to separate/divide your final mesh into its components, and then try to remove the extra material indices. It's not a lot of fun...

Since you've just used Blender for a couple of weeks: here's a quick how-to on separation ---

In editmode, hold mouse over any vertex, press L-KEY to select all vertices connected to the indicated one. Next press P-KEY, confirm that you want to separate those verts (i.e. turn them into a separate mesh object).

Once you've split everything into individual parts, delete all material indices (except one of course) for each object. If you start with the things that give you problems you might not have to do it to every single object...

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Post by lastfuture » Fri Mar 21, 2003 11:48 pm

thanks a lot, i will post further questions concerning the usage of blender to the q&a board at elysiun. i'll also try the procedure you have described.

in the meantime i have found yafray and yable and have tested them a bit

to get this thread more on topic, is there a way for you developers to implement yafray as an additional renderer? so basically to implement yable into blender and to make blender support photon/area lights and materials understood by yafray?
i'm probably wrong and it's a bad idea for some reason, but hey, there is a great lgpl raytracer and there's a python script that enables blender to export and render scenes in that raytracer... why not add support for it in the first place.

in case you don't know about yafray look at the gallery (but i think you already know it) at ... /index.php

i'm sure a great lot of people will apreciate if you could do that. after all it is even better than 3ds max 5's raytracer (which doesn't support any form of caustics for example).

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