IPAS3 Questions..
12 messages in this thread
Hi Gary,
I know that I can use scatter to randomly distribute a number of
boats across a wavy sea. I can also get the boats to float nicely by
adjusting the pivot point. How would I get each of these boats to bob
up and down – following the changing surface normals of a rippling
lake?
If I wanted a hole in a skinned vase, would I have to use opacity
and shininess mapping? I keep getting error messages at render time
if I do a boolean.
The ipas3 routines are quite outstanding – Well done!! Have you seen
the cover image on the latest 3D Artist? Do you know if Steve Sherer
(whatta guy!) used skin on the characters?
>> How would I get each of these boats to bob up and down – following the
>> changing surface normals of a rippling lake?
Create a scatter object for each of your ripple morph targets with the same
scatter settings. Morph between your scatter objects on the same frames as
your ripple morph. Since the scatter objects weren't manipulated on the vertex
level, you will have to reposition your morph object to match the position of
its morph target.
David answered your scatter question perfectly. Re putting holes in skinned
objects, the only way to do that is with opacity/shininess mapping like you
mentioned.
Re Steve Sherer's cover of the last issue of 3DA… very amazing image, but it
was done a long time ago, before skin existed. He's quite an incredible
modeler.
– G
Check out David's reply for your bobbing boats. As for the hole in your vase,
you'll have to use an opacity map. As we say in the docs, you can't alter the
vertex count of your SKIN template without invalidating the skinning. You can
move them, but you can't add or delete.
– Jack
I don't use/have SKIN, but it seems to me the inability to use
boolean subtractions and skinning could get frustrating. Can you
skin an object that has already been b-subtracted, or does the
skinned object need to have a completely uninterrupted surface…
wow, these things are incredible.
Skinned objects can't be booleaned. Skinning non-CSG booleans is
unbelievably difficult.
SKIN uses a lofted object as a "template" over which a Bezier patch is
hung. (You can use other types of meshes besides lofts.) Once you've
got your template, you can adjust any number of parameters that
affect the patch — such as whether it's open or closed around the
perimeter or length, the complexity of the patch mesh, its tension,
the type of spline used, etc., etc. And, you can change these
settings at any time before rendering — without having to recreate
the geometry. In addition, using another IPAS utility that comes with
SKIN, you can slice your template object into layers, which can then
be animated — either hierarchically or individually — while the
rendered Bezier path stretches over the animated segments.
The vertices of your original template object can be moved, but they
can't be deleted or added to. With all of the other fantastic
possibilities using SKIN, the lack of Booleans is not a big deal.
(Besides, if you count on Booleans for most of your modeling, you're
doing something wrong. <g>)
Ok, let me make sure I've got the slice/skin thing together. For
example, in the mouse image (from the catalog), if you skinned the sliced
mouse, you could then take those discs that make up his body and move them left
to right and the "skin" would stretch with it?
Could a routine like that be used to simulate, for a pitifully
non-creative example, an alien trying to come out of the mouse's stomach?
Your first question is correct. Re making an alien coming out of the mouse's
stomach, I'm not sure exactly what you want to do there — so it'd be hard for
me to answer.
– G
Re: Alien / Stomach thing (as an example).
If you took the top slice of the mouse's midsection (there is a large
gap in the demo's photo) and moved it a good distance to the right, the skin
would stretch from the correctly placed hip, to the skewed waistline, and back
again for the chest, right?
I'm still stuck on which disk to get first. It'd be nice if poor
non-professionals (yet) like myself could by IPAS' individually, but if you did
that, you wouldn't be much of a company, huh? <g>
Yup. It would stretch as you moved the x-sections around.
– G
While you can't boolean operate on the lattice for Skin, besides
everything that's been said, one of the benefits of Skin is in the
potential simplicity of the lattice. Talk about FRUSTRATING, try
modeling a complex object at the vertex level, with thousands/tens of
thousands of vertices – what a pain! With Skin, your lattice for a
very complex object may just require a few/few hundred vertices. This
is a signifigant time-saver, besides the very nice rendered results
you'll achieve.