I have some questions about Mental Ray (linear workflow , physical scale questions)

[manuqc]

Hi There!

 

Well, in my quest of learning a proper lighting workflow with mental ray, I am having some important questions that are still floating in my head, and I will like someone experienced with mental ray to help me clarify this issues. Thanks in advanced!

 

1) I was looking looking some tutorials from ZAP Andersson, and he says we can not use MR. EC. while using render passes (a&d output), only with master beauty output. But I will prefer tweaking my passes in AE rather than tweaking my master beauty output. So I am confused as he also says we should always use MR. EC control with photometric lights. But what is the point if I can not output the EC. with the passes? Question will be, is there an accurate manner to reproduce the same MR. EC in AE? (if there is a proper workflow I am missing please let me know as well)

 

2) How do I know if my input textures are linear or gamma corrected 2.2? I know most HDRs are linear 1.0, and I try always using "input gamma&gain" as Jeff Patton suggests. But now I am doubting if my some of my textures are linear or not. Lets say if I am using images from cgtextures or a 3D texture library, either they are photoshop corrected or not, should I always consider them as "gamma 2.2" on input? Is there a way to be sure?

 

3) Lastly, how do I know when to use physical scale units or unitless? I see most people use unitless. But I am having trouble with the "unitless" value I should be using. How do I properly enter a value for unitless? Should I always work in a real metric scale for this?

(and as an extra question regarding this one! how does a software like XSI deals with this if they dont work in a metric scale?, I ask because I work with xsi as well

 

Thank you in advanced for your time! I am trying to get serious about learning mental ray

for product visualization and vfx for film/adv. So hopefully you can lighten my way with your knowledge!

 

Regards,

 

-Manu

[manuqc]

Just wanted to bump this thread in case someone that has not take a look yet, wants to help me out. Thanks in advanced!