need help in mental ray

[Bussiere]

If you are using Mental Ray for Maya to light your scene you can download a plug in mentalray object lights V1.1 from highend3d.com that will make an object behave like an area light. It's a nice plug in but it can be tricky to set up and could use some refinement. It sounds like you are using 3DS Max, with a skylight. This light does not emit photons rather it adds ambient light globally to your scene. Depending on the lighting conditions of your interior a strong sunlight should be sufficient. If you are having trouble with bounced light filling your scene it could be caused by one of many factors: a lights intensity, decay, and photon energy. Global illumination settings and materials also play a crucial part as well. I could go on all day about the pains of Mental Ray but, my advice to you is to keep test rendering with a low amount of photons and low sampling. Try looking for tutorials on the web, and don't give up......:D

[Rimon]

first of all, thank u very much for ur attention. actually i use 3dmax. so do u know about a photons generating materials. thats what i'm tring all the time to find. actualy the main resone i need this material is that i need to get the effect of light coming out of an internal hemispher to put it infront of the window of my interion scene. i tried to use mental ray area light, but in the cylnder area light shap, i get constant photons and light intensty in all the areas around the window but if i use a self illuminating (photons generator) hemispher facing my window i think i'll get hight amount of light infront of the window and low light amount on the faces beside the window or faces on a steep angel to the window...i hope u undrestand my discreption. about using just the sun light in my scene, i tried to do this but i get a dark result in the parts not facing the sun light, and when i increas the global illumnation, photons energy or the light intensty, i get a very bright result in the faces facing sun light so it turns to be white will the dark areas start to be alittel brighter, just alittel than before. i also have one more question. do i have to increase the sampling valus and photons amount to a very big valuse to get a final clean rendring, or there is another methods, such as photons raduse?
i'm also looking for mental ray tutorials but i just find very simpel ones do u know any place to find better tutorials....i dosent matter actualy, just whatever u know, any site for tutorials......here is some digrames i made for the hemispher i tald u about

[psv]

there is no such a material yet fot max


but every material in max has a photon slot(mental ray connection) you should apply a photon shader on that slot,
usually a photon base..........shader

the result>>
faster render times(much faster)
control over color , intensity of reflected light via photon shader
every material in the scene SHOULD have a photon shader attached to it......if you use GI

use gi +final gather to smooth the result............be aware that the default of 1000gr rays is .....exagerated...try for tests 200-3000
be careful in cecking that your lights are emmiting photons(select light, right click, propreties, mental ray....pretty straightforward...

good lluck

go to mental ray shader discussion forum here on cg talk there is a huge .....,,,spring of khnowledge............i`m sure that in Egipt water is a precious thing...

[Bussiere]

Rimon,

I've prepared a little scene that uses a transmat photon shader to allow photons to pass through it but, the material has no transparency. Insted its self-illumination is turned on to 50 percent. This gives the image a light box effect if that is what you are going for.

Here is a link to the max file if you want to tinker with it.....


http://www.angelfire.com/pro/abdigital/MR_Example.max

Good luck and enjoy :cool:

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