PDA

View Full Version : Masking Shader as Bumpmap Problem

Milho
12-28-2002, 04:37 PM
When playing around with procedural shaders in Max i came up against a very confusing limitation of max.

My idea was to create a material which looks similar to a weird skin (very rough and basic as you will see).
It consists of a basic color, some blue "veins" and some big circles.
The bumpmap is similar except that it's black, the veins are grey and the circles white. This way i wanted to achive the effect that the veins stick out a bit and the circles stick out more.


So i created the diffuse map of several mix shaders with masks, a electric shader (veins) and a cellshader (circles).
I copied this shader to the bumpmap and changed the colors to black, grey and white.
But as a matter of facts, even though the map looked right, the bump effect did not appeared.
I rendered the map and used it as a bitmap bumpmap and got the right result (except it's not procedural).

After playing around a bit longer i arrived at the conclusion that as soon as you put a mask in the shader of a bump map the bump map does not react properly.

Conclusion: That sux. You hardly can make procedural bumpmaps.
Question: Did i do something wrong or is it a common limitation? How to avoid it?

Cheers
:beer:
Dave Black
12-28-2002, 08:09 PM
Not true in the slightest. A mask in the bump channel is not only possible, but key, and common.

So keep trying. A number of things could be causing this. I'd have to look at it closer figure out the problem.

My advice would be to go scientific.

Create a control. You postulated that max is incapable of producing a bump map when a mask is in the bump channel. PROVE it. Make a different map, simpler, and test this theory, adding effects until you get the error you are speaking about.

Now, it is possible that it's the electric type of map that is causing this. If you read the readme that comes with this freeware plugin, you will note that it cautions to use this map as a bump at your own risk, and that it's not meant as a bump map.

-3DZ

:D
Milho
12-29-2002, 09:52 PM
Sorry i'm answering so late. The 3rd party plugin was my fault but it is not the reason for the problem. Here a simple example:

1. Create a new Standard Material
2. Set Bump to 80
3. Set Bumpmap to Mix.
4. Set Mask of the Mix to Checker

Uncheck the "Show End Result" Button and you will see, that the Current Mix results in a checker, but the bump is not visible.
You can't use the color in Mix as Bumpmap if you have a mask.

5. Set the Color#1 of the Noise and the Color#2 of the Mix to Marble.

As you can see the mask works fine now. Parts of the bump are Marble and parts are Noise but that's not what we wanted.
Actually the Mask works but the resulting bump does not work as long as you give the Submaps another Map. So the mask it self does not represent a bumpvalue at all even if the color, which should be the effector for the bumpeffect differ.

This is not this bad and you sure could avoid masking this way but anyway it doesn't work like it is supposed to in my mind.


Another example:

1. Create a new Standard Material
2. Set Bump to 80
3. Set Bumpmap to Composite.
4. Set Composite Map1 to Noise
5. Set Composite Map2 to Mask
6. Set Mask to checker
7. Set Mask Map to Marble

The bump is correct. Uncheck the "Show End Result" Button and you'll see the checker with noise on one part of the checker and marble on the other.

8. Go to the noise map and set both colors to black
9. Go to the marbe and set both colors to white

Go back to the Composite Uncheck the "Show End Result" Button an you see a normal black and white checker. now check the "Show End Result" Button to see the preview. No bump visible allthough the map has 2 different colors.

Maybe it's a silly limitation but as you can see in the first example (the basic skin) this breaks your neck in some situations.

:shrug:
Dave Black
12-29-2002, 10:47 PM
why not just use a blend material then?
Milho
12-30-2002, 08:31 AM
I didn't say there were no other methods to do it. But you will agree that it is confusing that the bumb, even if the preview works, does not appear.

Anyway that's all i have to say. Hope we're all a bit smarter now.
So let's stop talking about it and hope they'll change it in future releases.

:thumbsup:

Mil
CGTalk Moderation
01-14-2006, 01:00 AM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.