Matte that receives coloured lighting

[Yecire]

As I've not yet been able to work out a way to get the red, green and blue blocks emit light (and maybe even generate caustics)

The only way to currently have objects 'emit' light in Blender's internal renderer is to use Radiosity (http://wiki.blender.org/index.php/Doc:Manual/Lighting/Radiosity/Rendering). There is also a custom build of Blender (http://www.graphicall.org/builds/builds/showbuild.php?action=show&id=854) that can achieve a similar effect using shaded Ambient Occlusion. For caustics, you'll have to wait ... development on various solutions (http://blenderartists.org/forum/showthread.php?t=146887) has started, but it may be a while before it's available, even for testing.

Of course, there are other external rendering engines you could use that have these features ...

I'm trying to make a matte ground plane that will also receive coloured lighting. At present I can only seem to get shadows to appear ... coloured light only shows if the surface isn't a matte.

Yeah, I'm not sure that's possible.

Generally, you will get more definitive search results and answers over at the BlenderArtists forums (http://blenderartists.org/forum/).

[DanielWray]

You can fake the coloured light and caustics.

For faking light bounce add area lamps with a very low energy level (0.300 max) and also make sure the Gamma leve is way down (0.100), adjust the distance (energy) just enough so that it hits the ground plane. Adjust the Hieght/ width (X/Y) so that it covers the width of the object and you'll want the hieght about 0.300 (this depends on your scene scale) now place the lamp just above the ground place and slightly angle it down towards the ground plane, now do a test render and see if it looks ok, if not, just adjust the settings until it looks good, you shouldnt need to adjust them too much though. This is the way that i fake light bounces in scenes.

Now for the cuastics, what happens with a ray traced solution is that light gets refracted and scattered (?). You can fake this with a spot lamp and a cloud texture. It's a very easy setup.

Add a spot lamp, change the energy level too about 0.300 and adjust the distance too a low level (3 to 6?), change the colour to what ever colour the transparent or reflecting object is. turn off shadows. Adjust the SpotSI and SpotBI (size and blending) up pretty high, this will make the fall off very subtle and blend the edge of the light into the colour of the material. Add a cloud texture and go into the colours tab, adjust the ramp to fade from the chosen colour to a dark grey. Now go into the texture options for the lamp, col should already be selected, click on the mixing method. Choose Add, this means it'll add the colour of the texture to the colour of the lamp and intensify the parts where it is being added.

Now to get a nice fall off you need to add a blend texture. I use the sphere option, go to the colour ramp tab again and change the colour from transparent white (on the right) to a grey (on the left). Now under the lamp panel texture settings, go to the map to panel and select "stencil", "No RGB" and click Add for the mixing method, col should already be selected, if not select it.

This should make that lamp project the cloud texture and it should look like caustics.

If you have any problems with it, just PM me.

Here is an example i made to show the fake colour bounce and the faked caustics.

http://img16.imageshack.us/my.php?image=cornellboxrendertest.jpg

http://img16.imageshack.us/my.php?image=cornellboxrendertest.jpg

[SpiderMunky]

Thanks for your help guys!

I've come a little bit further along, found a couple of other people having trouble with matte surfaces. Definitely no easy work around though.

Cheers for your tips on lighting etc. In the screenshot at the link below I've done a bit more experimenting. I put 3 different coloured area lights next to each other, seems to give a nice subtle bleed effect, and I must admit I do like blender's blurry reflections, somethign I definitely missed back in my 3ds max 4 days.

http://picasaweb.google.com/lh/photo/IfnpWvmbZ3zabFsBXZ3myg?feat=directlink

Hopefully I'll get some more time this week to work on it. Just need to work out whether I'm better off attempting to use booleans to cut the holes for the chain to go through or if I should model it in. It's good fun gettign back into this stuff!

Cheers,

Greg

[Yecire]

Blender's built-in boolean tools are not the best ... so I would recommend modeling the hole manually. If you prefer booleans, maybe try the MegaBool script (http://wiki.blender.org/index.php/Extensions:Py/Scripts/Manual/Object/MegaBool).

[FreakyDude]

Actually, I've never had more trouble with blender's boolean's than with say, max's booleans. You just need to make sure you model clean and plan ahead, so it's easier to cleanup afterwards. I've used blender's booleans lots of times for mechanical modeling.

[Yecire]

Yeah, I wouldn't say they're useless, or anything like that. What I've heard and seen from other users, is that the MegaBool script is better than the built-in booleans.

Many users complain that Blender's booleans are really bad, but I've never really used them ... I was turned off from booleans in general back when I learned to model as a 3dsmax user.

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