mentalray material dos'nt receive shadows

[atp-design]

why the objact has mentalray material dose not receive shadows!? please help,

[IceAged]

You need to be more specific. Can you post some images please and more details? I might be able to help then...

[nisus]

Hi,

 

We definately need more info about how you setup your MR-material and your scene.

 

rgds,

 

nisus

[atp-design]

ok , simple scene :two planes , one by standard material another by mentalray and a bitmap shader . ligh is standard and shadows set to raytrace.boxes has no material and turn on shadow casting.

[nisus]

Hi,

 

Your MR-material is not setup correctly. In the surface slot, you need a shader first (preferably DGSmap) and than you add your bitmap in the diffuse slot in the DGSmap. Next you can add more shaders that control photons, shadows etc.

 

rgds,

 

nisus

[atp-design]

thanks nisus .it's working now. but only dgs shader can make shadows?. I want to try some shader like watersurface and glass lume .basicaly what's difference between standard material and mental rays?? where we should use mental ray material and how should we set the parameters?

[nisus]

Hi,

 

The answers to your questions depend on the results you want to achieve.

There is no 'should' in the MR-world, it's about 'could'... and this is a catch of course, so much one CAN do even if it doesn't make sense at all...

 

Anyway, to help you out a bit.

I use DGSmaps (MR materials) for almost anything. Exceptions are glass (RTmaterial), water (lume/glass).

 

DGS is easy to set up, once you understand the concept. Light comes in, get absorbed or reflected, therefor the total of DGS can only be 1 or less.

You want glossy reflection, change G. The higher the value, the MORE relfection (not the more glossy!!!) You want specular reflections, change S. (Same here: high = more). Glossiness tells you HOW glossy it will be: low = wide, high = sharp. IOR doesn't need to be explained.

 

The largest difference between standard and MR-materials is that with MR you have perfect control over every parameter SEPERATELY, and it is exactly THIS that can speed up things for Arch.Viz.

Surface is independent from shadow, meaning you can control them seperately. No one tells you you 'should' but think 'SPEED' and you WILL use it. Same for photons/photons volumes in GI and CAU. Basicly SPEED will force you to be creative, otherwise, just make it real real, like real world (except for the rendertimes... my eye still renders faster than our network... lol!)

 

Anyway, the 'best' way to make a material is to instance the 'surface' shader in the 'photon' shader slot, so that the photons behave like the 'real' surface... this can be nice in an ultra real environment, but sometimes, all you need is a diffuse effect for the photons, because of calculation speed... MR materials lets you control seperately... so now just be smart about what you need and not ;-)

 

rgds,

 

nisus