phyiscal_light or equivalent in MR for 3ds Max

[Matt McDonald]

In Maya, there is a cool Mental Ray light shader called physical_light. The reason it's so cool is that it has a function called threshold which limits the tracing of shadow rays (this is similar to the portal light shader).

 

I'm trying to find the same thing or something similar for Max. It is mentioned in the Mental Ray help documentation but it does not appear to a hidden component.

 

My interest is in limiting shadow rays. I have a volumetrically large scene with lots of light sources. Shadow samples are set at the minimum (I'm using unified sampling) and I'm shooting something like 200 shadow rays for every eye ray. I'd like to try and reduce this number but I'm not super interested in turning off shadows of various lights.

 

So...if you have any suggestions, I'd love to hear them.

[thorsten hartmann]

Hi

 

 

edit: ah sorry i mean a other photometric_light shader

 

PS: if you need this Shader

 

- go to \3ds Max Design 2014\NVIDIA\shaders_standard\mentalray\include

- open physical_max.mi File in Notepad.

- edit this code ...

 

gui "gui_physical_light" {

control "Global" "Global" (

"helpCHM" "MI_Shaders/mr help.chm",

"helpLink" "/shd-2_2Light_Shader_physical_.html#physicallight",

"uiName" "Physical Light",

"category" "Light",

"hidden"

 

to

 

gui "gui_physical_light" {

control "Global" "Global" (

"helpCHM" "MI_Shaders/mr help.chm",

"helpLink" "/shd-2_2Light_Shader_physical_.html#physicallight",

"uiName" "Physical Light",

"category" "Light",

# "hidden"

 

the hidden line need a "#"

 

mfg

hot chip

Edited April 20, 2013 by thorsten hartmann

[Matt McDonald]

Thanks Thorsten

 

It's the "threshold" part I'm interested in. Where is there a similar control in Max?

 

Matt

[Matt McDonald]

Thanks Thorsten!

[thorsten hartmann]

Ah Sorry,

 

i have mean a other photometric Light Shader. You are right the Treshold is only by the physical_light Shader. I have update my answer bevor.

 

mfg

hot chip

[Justin Hunt]

Set your far attenuation

[Matt McDonald]

I think Mental Ray ignores the attenuation control. It seems to in my test scene anyways. With no attenuation, in my test scene I am shooting 11.15 shadow rays per eye ray. With far attenuation set to 3' (lights are 25' from any object) I still get 11.15 shadow rays.

[Matt McDonald]

In another forum someone suggested I try the Wom_Archlight. I've got it working, kinda. It looks promising. It seems to have all the controls you get from a photometric light via the max UI + the threshold parameter I'm looking for. Because the shader is intended for XSI or Maya, the UI in Max is crumby but I think I should be able to get around that. Maybe.

[thorsten hartmann]

Hi Matt,

 

ah looks good, i have download V1.2 and will write a GUI for this Shader. For me is important the Mesh-light Shader.

 

mfg

thorsten

[Matt McDonald]

Thanks Thorsten

 

Keep me posted. If there is anything I can do to help, let me know.

 

Matt