Otherwise you loose precision in the meshes.
Second Life uses 2 slightly different Rig definitions for the System character and for your Custom meshes. And this has major consequences and you end up with a shape that no longer matches to the System character mesh, even when the mesh itself does match perfectly on vertex level. That means for the Collar bones and Shoulder bones: When you move the Torso Shoulders Slider then it just does not work any more. Technically it loses the ability to follow translations. When a Bone has a Joint Offset then it gets treated slightly different by the Appearance system. But the Mesh gets bound to a PIVOT Rig and so it will match better when you compare it to the System Character. When you use a clean PIVOT Rig for your mesh character then an import with Joint offsets uncorrectly detects joint offsets for some bones. Each vector defines the distance to the parent joint: Below you find an excerpt of the Rig definitions. The reason for why those 2 rig definitions exist is unclear and buried somewhere in ancient history of Secondlife. In short POS and PIVOT are 2 definitions of the Secondlife Rig which are almost identical but differ a tiny bit from each other. But what is that and how do we work with this? In fact this is one other source of misunderstanding, misbehavior and its quiet badly understood by everybody, even by LindenLab them self (i believe). You may have seen that Avastar supports 2 Joint Types, namely PIVOT and POS. Now you wonder why this is important even if you do not at all use the appearance sliders? In fact the appearance sliders take effect even when you wear a default shape. So even if the mChest bone plays no role in the character weighting (in our example) it still affects all its children as far as appearance sliders are concerned, because it reacts different to the appearance sliders when it has no joint offset defined. This is done by using the Fitted Mesh bones, or more precisely the Collision Volume Bones to the mesh.Īnd this is evil! The problem is with the Appearance sliders: In that case any joint translations (location moves) defined in the appearance sliders are not applied to bones with joint positions. The basic idea is to let more Appearance sliders control the mesh. This is where the Fitted Mesh addition steps in. However this means you create your content by using the Second Life Restpose which does never match the actual Shape that you use in Second Life.Īctually we want to create attachments which can be adjusted (fitted) to any shape.
But this information is normally not available outside of Second Life.įortunately you can get around this problem by using the SL Restpose for your work in your 3D Editor. So if you want to create a specific mesh attachment for a specific shape then you need to know exactly how the shape values are related to the joint positions (and bone scales) of your particular shape. This is controlled via 20 of the available shape parameters (appearance sliders) for the Legacy Skeleton and 40 additional parameters for the Extended Skeleton (mostly for the Face expressions and Hands). It is important to always remind that your Avatar Shape settings in your viewer effectively change your skeleton’s joint positions and Bone Scales.
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