illuminating textured object

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illuminating textured object

Postby frozenb » Thu Jul 01, 2010 6:50 am

Hi!

I have some little spikes textured and I'd like them to emit light. They would be small light sources illuminating only a small environment around them and it would be crucial for the texture to be recognizable.
Some references:
http://img8.imageshack.us/img8/7720/ragnaros.jpg
http://www.danscottart.com/Images/HammerOfRagnaros.jpg

I tried to use a matte material with emission on and texture: imagemap. The problem is that however low the gain, power and efficiency values are the spikes are as bright as a comet, especially when there are more of them. /* http://img42.imageshack.us/img42/7994/legendary70testemitsucc.png <- it is far too bright :( */

I wondered if the size of the objects count but i didn't found any information about that.
I welcome any suggestions
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Re: illuminating textured object

Postby xray » Thu Jul 01, 2010 6:56 am

Tonemapper is the thing you are searching for, adjust the values while rendering:

http://www.luxrender.net/wiki/index.php ... ne_mapping
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Re: illuminating textured object

Postby heretic » Thu Jul 01, 2010 3:24 pm

For this issue tonemapping is a good start, still there are some options/alternatives to keep in mind:

1. add a mantle to those spikes: copy the spikes emitting light and displace along normals by eg. 1-100um, same material as original object. Then you can just apply a mix with null material and a blend texture to mix both materials in a way that the light parts can be seen. To change the color you might use also absorption.
2. like 1, except you dont create a second material but directly blend the material with emit to the material without emit (everythign else the same).
3. tonemapping: tonemapping alone with LuxRender might not do the job, since LuxRender tonemapping is global aka it effects the whole picture. In this case by tuning the light, the whole picture becomes darker. Instead Id suggest using qtpfsgui and apply Reinhard '02 tonemapper, which is a local tonemapper and computes tonemapping for areas of a picture (instead of reinhard '05 in LuxRender).
4. blackbody: create a blackbody material preferably at app. 3500°K and mix with the non-emit-material

Just my five cents on your options which might deliver varying interesting results

_heretic
-----
3D with blender since November 2009, LuxRender since May 2010. http://www.flickr.com/photos/nur-bilder/
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Re: illuminating textured object

Postby frozenb » Tue Jul 06, 2010 7:54 am

Thanyk for your tips!
Seems like playing around with light groups and tone mapping have solved the problem but i will keep your advices in mind :)
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