Specular Pass Question?

Playdo

I've rendered out a load of Passes in Render Elements, Max, Mental Ray, so I can understand how they all 'fit' together.

My A&D Level Specular pass shows information but the A&D Output Specular/A&D Raw Specular/Specular passes do not show any information. Why is this? If there's information in the level pass then wouldn't it show up in the raw at least?

A&D Level Specular Pass:

Eric Chadwick

I guess it would depend on the definition of what each pass type contains... what is Level vs Output vs. Raw vs. Specular. Anything in the Help file about them?

If your material doesn't contain those elements, then you'll probably get empty passes. Like if you tried to render a Reflection pass but had no Reflect ingredients in the material...

Playdo

I know that Level contains the 'level' of specularity
Raw is unadulterated
Output = Raw x Level.

There's nothing in the material's specular slot, but there doesn't need to be does there? Looking at the Level image posted, there's specularity present?

Eric Chadwick

What is your material setup? Are you using an Arch & Design material? There might be a default specular level, but no defaults for the others.

Playdo

Yes, it's just an A&D material with the reflectivity and glossiness turned up.

Eric Chadwick

Right, so I would guess your material has no Output, no Raw, and no Specular... so those passes remain empty.

Playdo

Is Specular not on at default (I can't check 'til Monday)? What do you mean by the material has 'no Output, no Raw'? I didn't think there were settings for this. I appreciate the info.

Eric Chadwick

Do some research, read the Help file, learn what these passes actually are supposed to contain.

Playdo

It's already mentioned that these passes contain the various types of
Specular output. You say that an A+D material has 'Output and Raw' inputs, something I wasn't aware of.

These forums are for the sole purpose of posting questions, things can sometimes be understood more clearly when asking a direct question.

divi

http://docs.autodesk.com/3DSMAX/13/ENU/Autodesk%203ds%20Max%202011%20Help/index.html?url=./files/WS73099cc142f487553b93539f117a2602bd5-6043.htm,topicNumber=d0e371172

i dont think that these forums have the sole purpose to reiterate answers you can get from the actual software documentation.

Playdo

I already read that. I can't see it reiterating my answer anywhere. There's a saying that goes 'it's easy when you know how' .. remember it!

divi

raw shows what would be reflected , level shows where and how much would be reflected and output is both combined. so if theres nothing to be reflected like an environment map in the reflection color slot the raw pass wont show anything. and since the output is raw * level it wont show anything as well.


Reflections: Raw (left) * Level (center) = Output (right)

+

With most of the elements, raw is the unscaled contribution, and level is the scaling, and the output component, calculated by multiplying the raw and level components, is the resultant contribution of the element to the full rendered output. The level is often related to an input parameter (or combinations thereof), and has been modified to abide by the energy-conservation feature of the Arch & Design material.

tell you just that.

Eric Chadwick

Playdo wrote: »

These forums are for the sole purpose of posting questions, things can sometimes be understood more clearly when asking a direct question.

Yes, post questions. But you will always get more information if you do your own research first, and ask questions later.

This is worth its weight in gold:
How To Ask Questions The Smart Way

r_fletch_r

Try rendering your passes as HDR files with a 32 bit frame buffer. Then edit the exposure in PS. I've had some odd problems sometimes with this. Exposure control sometimes does some odd stuff
if this doesnt work post a file inwhich the effect is evident. it should be easier to fix if I can mess with it

Playdo

We're going round in circles here. The quantity of specular is presently shown in my Level Specular pass.

From Max Document: 'Raw is determined by the Reflection - Glossiness value'

As stated, my glossiness value is set to high.

What else needs to be changed? There's a HDR in the environment. I'm getting my reflection passes coming through correctly.

Playdo

Ok, thanks, r_fletch_r. I'll look into that.

@Eric: I do do my research, but at the same time I'm fairly new in this field so it can still be confusing understanding it all without asking specific questions.

Playdo

I just placed an omni light in and it's now producing spec passes. I originally only had two MR Sky Portals and it looked as though there were spec highlights present.

I've attached the file Fletch, I'm sure it's an obvious solution for someone who's good at passes. Are the Sky Portals actually producing spec highlights?

Only MR Sky Portals:


Max File:
http://www.mediafire.com/file/nmjzzxzdnmd/Cubes.zip

Eric Chadwick

I would be surprised if those produced specular, since they're "area" style lights, meaning there's no single location where the specular would come from. A specular highlight is basically a simulation of the reflection of the light source itself. But I haven't used MR a ton either.

Playdo

I've got 2 white planes in the scene to cast highlights but without them there are some highlights running along the top edges of some blocks. If these aren't specular then what else are they? Does it just count as part of the diffuse? I always thought that any highlights on corners were specular highlights from the light source.

I've come across many different tutorials etc on passes but never found a clear, bulk of info explaining everything about all the passes and how they're composited. If anyone knows of one, please post.

THE 5

Not shure, but for A&D Materials it could be...

... dat?

Playdo

That's the one 5, thanks. I wouldn't have had a clue to search for that in the Max documents