Hey guys, Tim showed me this thread and I figured I would try to explain things a bit if I can. But first let me say I'm a big fan of XSI and the work you guys do, though I have never used it myself, my officemate does and i find it pretty awesome overall.
OK... I'm going to start with going through Matt's mail and see if I can clarify things >>Basically the guy took 24 minutes to explain a 2 minute concept. Its true, I did take the long way around. My goal was to make sure that everyone... if they were complete newbies, or seasoned veterans could grasp things. I have been amazed at how hard the idea of abstracted weights has been for people so I took my time. I was also asked by Hippy to breakdown somethings in the way he wanted so there was some time there too. >>The main point is Modo can define the order in which deformers are evaluated >>to solve envelope weights, and envelope weights are assigned using 'weight >>containers' which are logical assignments of points to deformers. A >>different kind of weight map. You can assign a standard weight map to a deformer too, weight containers are just another method to do so. As Tim points out, a Weight Container is really more like a Weight Map Item (or Proxy) it allows you to feed them into deformers even when no points or "weighting" has been added to them. The key concept here is that with WCs you can build a complete rig with no mesh involved at all... load this into a scene and then just add the points you want to weight into the WCs and the deformation setup will work on them. Once you do add the points in them, you can adjust the weights like you would with any weight map. >><SNIP>In Softimage you'd normally place the bones into a hierarchy and assign >>the weights to the joints. <SNIP> >>In Modo, the weights were assigned to the individual bones via 'weight >>containers' (their version of a weight map), but the bones were not placed >>into a hiearchy. <SNIP> Modo allows you to work in this traditional method too... add a set of joints, in a hierarchy, to a mesh through the "bind" command and all of the joints will be assigned a set of weight maps. You can then add or subtract weights like you are used too... if you add to one joint it will take away from another. The WC way of working is not the only way. Also there is no "metadata" on a Weight Container, as far as the system is concerned its just another weight map. Its just defined a bit differently and provides a more flexible approach to how weights, rigs are applied and created. >>The part I take issue with is not having bones in their usual places will >>make it difficult for animators to judge how the character is moving when >>adjusting keys. After all, you don't generally envelope a rig unless it's >>expected to be animated, so why disassociate the bones from the animator's >>perspective? I did not cover all the different ways to use Order of Operation (OOO) deformations with using a hierarchy... so let me try and clarify a bit. You can use a standard hierarchy of bones if you want with the OOO method (with or without using Weight Containers) you just need to tell your joints to pass their local transformations into the deformer (which is just setting on the joints themselves). So you could have your standard set of joints and the animator can have access to them in the way you describe there. There are also other ways to provide controls to animators that don't require the joints... more on that another time. Anyway, I didn't show local transformations in the video because I was trying to make the idea of OOO very clear. To show the joints moving in local space seemed like it would cause more confusion. >>The part of greater interest was pre-evaluation and post-evaluation events >>which gives the artist the opportunity to further modify the resulting >>deformation as each >>deformer is evaluated. This is THE most important part of modo's deformation pipeline... Order of Operation. Its something I was exposed to at Rhythm and Hues and it was a mind blowing, eye opening experience for me. When I saw that modo was tackling deformations in the same way I was very excited. I was also impressed that Luxology was able to come up with a way to provide the standard normalized approach to weighting in a OOO system (using normalization groups). Basically you can have your deformation cake and eat it too. >>The example given was not very good as it could be easily replicated using >>linked parameters to drive a lattice or some other easy control, but in more >>complex cases could be useful for sculpting the envelope deformation in very >>specific ways. That example was more illustrative of the issue at hand than a true practical case, that said, its how I would handle sculpt offsets for an elbow I was rigging too. I personally find it about as strait forward as you can get. I like having explicit point control over my shape. >>You can replicate most of it in softimage using a different strategy than is >>typically used, but some of the more advanced stuff, such as compensation, >>would require a custom envelope operator or ICE. Of that I have no doubt... the stuff you guys can do in ICE is down right amazing :) -Rich
