View Full Version : mia_material+gi

04 April 2007, 06:20 PM
I have built a simple scene and all objects have mia_material assigned and I activated GI.The problem is that noting is rendered and in output window the message is "no photons stored".
However I manage to reneder the scene by plugin mia_material into the photon shader of the mia_material SG. Is it right what i am doing ?Is any other way to make mia_material to work with GI ?

04 April 2007, 07:52 PM
Maybe the normals are pointing the wrong way... Maybe your scene is too small. If you create a sphere and use a directional light the 99% of the photon doesn't hit anithing so nothing is stored.
Hope it help!

04 April 2007, 08:11 PM
thanks for reply,Gabba
I double check the normals before , the scene is modeled in world size,I,ve created a sphere but I use a spot light( quadratic decay) all the textures are gamma corected and I use Ctrl_buffer
anyway,.... is working only if I plug the material in the Photon Shader of MiaSG-
The other problem is that I've maped a wood texture on the floor shader (implicit for the photon shader since I use the same material) and now all my walls are brown-red from that texture.
How can I limit the affect of the floor and still having a physically accurate shader ?- because I can simply duplicate the mia material ,make it white and plug that in the photon shader - all my walls looks white... but I am sure that is something wrong proceeding like that....:sad:
04 April 2007, 08:25 PM
... is working only if I plug the material in the Photon Shader of MiaSG-
.well, that's simply what you have to do, manually. from maya8.5 there's support for material phenomena so you could wrap the thing in a phen to having not to manually plug everytime your material connections. didn't tried myself.

How can I limit the afect of the floor and still having a physically accurate shader. on my part I have not this kind of problems. but you can plug another mia_material in the photon slot and there tweak something to get out what you have in mind. another solution could be to plug a ray switcher on top of the shader graph and there maybe supply a different texture(desat, so you'll get milder bleeding) only to the photon rays.


07 July 2007, 06:22 PM
to stop your floor affecting the rest of your scene you can go down to the Mental Ray rollout of the shader, and uncheck derive from Maya. Then hit "take settings from maya" and reduce the reflectivity, diffuse and colour. These will not change the shader but will only reduce the energy photons have once they bounce off the floor.

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07 July 2007, 06:22 PM
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