View Full Version : Key Vertices- or Point-Transformations in XSI
07-14-2008, 02:18 PM
Good Day everybody,
although I found a thread (http://forums.cgsociety.org/showthread.php?f=24&t=568229&highlight=animate+vertices) that dealt with the theme, it wasn't of much help...I still wonder if it's possible to move some of the vertices/points (of a grid, for example) with the Proportional Modification Tool, set a keyframe for their position, go to another frame, key again and so on.
The goal is to directly animate the Vertices/Points moving through space. The help states it can't be done with standard keyframing (unlike in maya, where the SetKey Options allow to toggle on "Control Points").
Blendshapes are not an option, so are clusters. I also don't mind if I get thousands of FCurves in the Animation Editor; I was just wondering if there is some hidden way to accomplish that, a script that could be useful (already looked into that on highend3d as well...).
Any help is geatly appreciated:)
07-14-2008, 02:21 PM
I have to ask, why are shapes not an option?
This is exactly what they are meant to do, and there is no better method to deal with it than one to be honest.
07-14-2008, 02:37 PM
You could use a cluster with a weightmap falloff. That would be the closest thing to animating points with the proportional modeling tool I think.
create a weightmap > select all the points in the object (or make sure all the points in the weightmap are included ) > Create a new "cluster with center" > in the cluster center PPG connect the weightmap to the "Amplitude" slider.
animate the cluster center for maximum effect :D
07-14-2008, 03:16 PM
Whoa, you guys are quick!:)
Here's my problem in depth, I also attached two images of the process:
Out of curiosity, I'm trying to recreate a Deformation Grid like Bernhard Haux (http://www.characteranimator.com/movies/character_td.html) used it in his short "Me and my bike". So I got a Grid, surface-deforming a lattice, which deforms the object itself. Grid and Lattice are nested in a transfogroup and parented to the Camera I'm looking through. So far the script works, although the setup is not automated.
Some time ago, I tried the same in Maya and that went really well, except for the fact that Maya's softselection-deformer doesn't come anywhere near XSI's "true" soft-selection. Further more, now the deformer was moving but not the vertices themselves, so I couldn't key their movement directly. I ended up animating the lattice's points directly but always felt it was a shame that there was no possibility to smoothly sculpt the character.
Enter XSI and it's lovely Proportional Modification Tool! The setup is similar, points can be moved with ease and nice falloff - but can't be keyed, at least I don't know how.http://rapidshare.com/files/129643050/Undistorted.jpg.html
That's why it would be very nice and convenient to avoid Blendshapes or clusters at all.
07-14-2008, 03:21 PM
I'm sorry, I'm still unsure as to why you can't use shapes.
Is it because your lattice is in the modeling stack and you don't get the shape result? If that's the case just move the lattice over the shape combiner or in the animation stack (not in secondary shape though, so you still get a way to sculpt on top of it all and then recommit it back further down the stack).
Is it something else?
I understand what you're trying to do but not why clusters or shapes are inconvenient :)
07-14-2008, 03:33 PM
Brilliant, that's it!
I tried earlier to store and apply shape keys but it gave me error messages that I, new to XSI, didn't fully understand. Now it works like a charm and you're right: this way blendshapes are as good as keys in terms of animating the grid's deformation.
Thank you very much:D
07-14-2008, 03:54 PM
One quick note before it leaves you stumped in your next steps:
The secondary shape animation stack is one of the coolest but most misunderstood functionalities of the op stack when combined with shapes.
While deformers and all can live in there just fine, some times people model modifications to a shape in there because they want it after an envelope (IE: corrective shapes) and then when they save it wonder where it went or, if they find that it always goes in the normal shape combiner, wonder why it's not working.
Shapes are just a bunch of vectors.
Modeling one in the secondary stack is possible, and when you save it all modifiers between that and the shape combiner are accounted for and compensated when the shape is saved, so it gets applied normally (without freezing anything you don't want frozen) but still deforms things the way it was doing when it was at the top of the stack.
It can take a little bit for the vector challenged to exactly grasp the above, but a little bit of experimentation and manual pages flipping goes a long way and usually resolves in one of those "Ahhh" moment. it's actually a pretty nifty feature and I advice you get accustomed to it if you plan on doing a lot of shape and op work structured the way you're doing.
07-14-2008, 04:54 PM
Thanks for the advice, I'll look into that...pressing F1:surprised
07-14-2008, 04:54 PM
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