1.5 skinwrapping

Krakatoa for 3ds Max
1

I haven’t been able to get the Krakatoa skin wrap to work yet. I read through the online docs but those don’t have a step by step example or max file to download.

I’ve been trying it with just a simple PRT and a sphere. I keep getting the same error as I would get with an Invalid Teapot.

Something like this:

“cannot convert the skinwrap object to a TriObject”

Help please

Thanks

2

It sounds like you have the modifier on the sphere and are trying to point it at the particles, or something to that effect. The Krakatoa SkinWrap should be placed on the PRT Loader, and the pick button should be used to select the Sphere object.

3

That’s interesting as Skinwrap in max works the opposite way. However, when I tried to do it with the WSM on the PRT and then “Pick” the Sphere I don’t get an error but nothing happens.

The Sphere doesn’t move with the PRT nor does it deform.

Also when reading the Docs it states you can use it in place of Max’s native SkinWrap function. I found that not to work either on simple objects. I tried that method with a box & sphere and it didn’t do anything. What was also strange is that when I had “Autokey” on I could move the box and the sphere would follow, which let me to believe it was working. However that was only when I was moving the object around in the viewport. Once I let go and turned off Autokey the box moved and no longer did the sphere.

So at this point, I feel like the Krakatoa skinwrap function isn’t working at all. Not with a PRT or Object to Object.

Maybe there is something I’m not doing but it sounded straight forward and I’m very familiar with skinwrap.

Any other suggestions or Max scene files?

By the way this is tested in max2009 64bit

Thanks

4

Just to clarify, the Krakatoa SkinWrap can be used to animate a particle cloud, based on the deformation of a geometry object. It does not support the inverse operation.

I’ll ask Bobo to make a short tutorial for the SkinWrap in order to clear up any outstanding issues.

5

I will provide a step by step tutorial soon, but here is how it works and why it might “fail” for you:

  1. Create a Sphere with radius of, say, 50
  2. Create a Geosphere with radius of 50 and the same center - both look similar, but topology is completely different.
  3. Add a Bend modifier to the Geosphere, go to frame 100 and animate the Angle from 0 to 90 degrees. So frame 0 is 0, frame 100 is 90.
  4. Add a Krakatoa SkinWrap to the Sphere and pick the Geosphere as the skin object. Notice that the Base Frame is 0, so it will take that relative vertex position on frame 0 and move the vertices on the following frames to match the motion of the animated Geosphere.
  5. On frame 100, animate the number of segments of the Sphere (the driven one) from the default up to, say, 32.
    RESULT: The topology of the deformed object is changing over time, but it still moves according to the animation of the Geosphere we originally bent!

The same applies to particles - they can have their own animation and change from frame to frame, but will still follow the animation of a deforming mesh.
This is exactly the opposite of what Box #2 does with particle skinning where particles drive a mesh. It lets you animate characters made of particles. We used it with our own blob mesh technology to grow the Fu Lums in the Dragonball movie for example.

Now if your deformer object is not changing between the Base Frame selected in the Krakatoa Skin Wrap and later frames, the deformations won’t be transferred correctly. For example if you align the two spheres on frame 0 and then bend the Geosphere at 90 degrees WHILE ON FRAME 0, the Sphere won’t follow because it will take frame 0 as the Base and will recalculate the relative positions based on the already bent Geosphere. You must ensure that the two objects (or mesh + particles) are relatively well aligned on the Base Frame, then have animations on later frames to get your motion.
Typically, we would build a character in a T-pose on frame 0 or earlier, create particles out of it on that frame in the same T-pose, then have an animation of the character on later frames and our particles would follow. We usually bake the deformed particles to a new PRT sequence to avoid constantly recalculating the deformations (it is not very fast I must admit), and we end up with a cloud that behaves just like the original character…

6

OK great this information does help.

Look forward to a clear tutorials.

Thanks

7

This is not exactly a tutorial (since we cannot provide the character animation used in it), but it is a discussion of some possible workflows related to the Krakatoa SkinWrap WSM. It also includes the sphere/geosphere from my previous post with some illustrations:

software.primefocusworld.com/sof … ations.php