View Full Version : cloth fx using weight map?

04-28-2005, 11:08 PM
According to the LW8 manual, we should be able to use a weight map to regulate the collision surface in dynamics/cloth fx. But exactly how it is used is unclear (at least to me!)

I have been experimenting with a pair of pants i modelled, colliding with a body wearing them. I'm trying to get the fabric at the knees and ankles to sag, and the rest of the pants to remain fixed. So, i made a weight map where areas around the knees are various values, and the rest of the pants=0. Figuring that the >0 points should respond more to the gravity setting than the 0 points...right?

Problem is, it works almost opposite. The pants fall down around his ankles (ok, a hoot, but not what I'm looking for...). Reversing the weight map points does not reverse the result. So I'm very confused.

I've tried many combinations of where to use the weight map, "all", and "none" in Basic/Fix and Collision/collision detect, Interaction, etc., and can't find anything that works.

Does anyone know HOW to use a weight map to affect cloth fx?


04-29-2005, 04:26 AM
Have you set the 'Base' value?

In the Fx button where you set the weightmap, the bottom item item is a 'Base' which is the value used where the weight map is 0.

04-29-2005, 09:59 PM
Dodgy, thanks, but i don't get this at all.

On the Basic tab:
There are 6 Fx drop-downs next to things like Weight, Spring, Viscosity, resistance, etc. In each of those i have the option to choose my weightmap OR 'base'.

Am i supposed to pick 'base' there, or the weight map? Why? Anyway, I'm not trying to control spring, viscosity, etc, by the weightmap -- i just want to control what points are being moved (or fixed, if that's the only choice), and by what percentage (compared to each other).

There is also the Fix drop-down, where I also have the chance to choose the weightmap. How does that relate to these Fx choosers? Putting the weight map in the 'Fix' drop-down didn't work, even when i tried reversing the values.

On the Collision tab:
I could choose the weightmap on the drop-down list by 'collision detect' and 'interaction'. The explanation on these things is minimal at best in the manual.

None of these things work as I expected from the minimal info in the manual.
And I have found nowhere an explanation for how these things work together in regard to a weight map. I fiddled for hour with different settings that made sense to me (and also some that didn't), and no luck.

So if you or anyone can explain, please ,please, do!


04-30-2005, 06:37 AM
No, you don't choose map OR base, you choose map AND base...

Let me explain.

Your weight map goes between 0 and 100%. The value in the field is used where the weightmap is 100%. Then you set the Base value. This is the value which is used where the weightmap is 0%. And lightwave interpolates between these values to get the rest of the (for example weight) values.

So if your Weight=20, and you set the Base to be 10:

At 0% at a point, the point weighs 10.
At 50% at a point, the point weighs 15.
At 1000% at a point, the point weighs 20.

You can use a weightmap to determine whee collision occurs in ClothFX, I think it happens wherever your value is >0. Since it's either on or off, a selection map is probably better for this.

05-03-2005, 04:17 PM
OK, thanks for explaining this!

I guess it just doesn't do what I was trying to get it to do..too bad, would've been very cool.