View Full Version : restrict displacement with a weight map?

04-23-2003, 08:10 AM
I'm trying to follow a tutorial in the July 2002 issue of PCMAG, that has you put a displacement map on a sds cylinder. To keep the bottom from displacing as the top does, it tells you to "switch back to modeller and add a new weight map to the liquid (the sds cylinder). Make sure the point at the top are set at 100 percent and use Set Map Value on the maps tab to give the remaining points a weight of .01 percents."

I swear i do this and it does nothing. The displacement map (in layout) goes right through as if have made no map. I know I have a map in modeller. I can see the respective colors in the weightmap view. Its red at the top and fades to the regular green.

Any ideas here?
Or tuts that deal with weight maps for in depth?

How does my displacement map "know" to follow the guidelines of the weight map I have made anyway? what if you made a few? how would it know which one?

I greatly appreciate any help,

04-23-2003, 09:48 AM
You have to stack a b/w gradient with input set to your weightmap and mode set to "alpha" on top of your turbulence. That will do the trick.


04-23-2003, 09:56 AM
Interested to see if this works.
I've not been able to get it to. Mailed Newtek about it. No response. Ended up saving full displaced object as a transformed object, then using the weight map to selectively apply background as endomorph. Also worked.

Everything worked fine for a normal bump map, though. Go figure.

04-23-2003, 12:07 PM
Yes! It worked.

Thank you Mylenium!!!!!

ok here's the sum up for dobermunk:

went to the properties (in layout) of the object i wanted to put a displacement map on. went to "deform" tab and clicked on the "displacement map" textrue button to access the texture window.
layer type-procedural texture displacement axis- Y
Procedure type-Turbulence
all others were kept default

ok then in same wiindow:
add layer-gradient

for this new gradient made this changes:
blending mode-alpha
Input parameter- wieght map
weight map- WaterWieght( this is the specific weight map name that I created in modeller.)
on the gradient added these keys:
one at the top and set it's value to -1
one key in the middle with value set to 0 and one key at the bottom with value set to 1. So my gradient goes from black at the top to grey in the middle to white at the bottom.

Clicked "use texture" and now it does what I want. The displacement only effects the top of object (Y axis) and not the bottom of the object.

btw- I'm making a pot of boiling water. Next I went back to the "turbulence" layer and clicked on the "Position" tab. Here I clicked on the envelope button and changed the graph so that the turbulence moves over time on the Y axis. This gives me the effect of the surface of boiling water.


04-23-2003, 01:17 PM
Yepp, exactly, carbon. I think dobermunk simply didn't take care that weight maps range from negative values to positive ones and do not start at zero. If you try to work with them in this manner you will see no results. With bumps however it works in this way. At the core of this is a simple mathematical problem but i will spare you the details.


04-23-2003, 02:51 PM
Grrr. :mad:

I'll have to look at the object again. From last year. I tried everything and the -100 to 100 range is familiar to me.

I was working on an object for a 3D print. A world cup trophy.

06-21-2003, 11:44 PM
First let me say thanks to this thread I figured out how to do the same thing. The only difference for me was for the Turbulence Layer when I changed it to Textured Displacement it did nothing but when I changed it to normal then it used my weight map. Oh well, I'm just glad that it worked. Thanks guys!