capture based on selection

[hatrick]

Hello,

Is it possible to capture geometry based on primitive selection ore primitivegrouping when rigging a charakter ?

thank you

HT

[old school]

Sure. The Capture Geometry Shelf tool only allows you to select the entire skin object. Using the viewport interactively, your first question has to be responded with "no" but you can certainly capture by point groups.

You can use multiple Capture SOPs in a row, each capturing a specific group of primitives. Just make sure that the subsequent Capture SOPs have the "Destroy Existing Weights" toggle off or else the last Capture SOP wins.

It's easiest to just do a base capture with the entire skin and bones first using the Capture Geometry shelf tool: select skin, enter, select bone hierarchy root, enter. This createst the Capture SOP and the Deform SOP for you. Next copy/paste the Capture SOP and add the point groups that you want each Capture SOP to capture. You can also modify the bones used to capture the skin at this time in the Extra Regions parameter. Press alt-e to get the parameter editor to parse the bone list if you wish. I don't do this myself. You are one typo away from disaster. I just leave this alone unless some bones get re-named and it doesn't get picked up here.

Please make sure to turn off the parameter "Destroy Existing Weights" on the subsequent Capture SOPs so as not to obliterate previous capture weights.

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You can also use Capture Layer Paint SOPs to add additional bones. This is usually reserved to bones added AFTER the initial capture. It's best to do the bulk of the skinning with Capture SOPs and leave the Capture Layer Paint SOP approach to adding additional bones added later in the process. Like belly jiggle bones, bones for facial rigs, ears, etc. The stuff you forget in the inital bone hierarchy.

When I add new bones to the capture tree in SOPs, I will dedicate a single Capture Layer Paint SOP just to add those bones in a region and paint their initial weights to the skin. I try to refrain from painting other bone weights in these Capture Layer Paint SOPs. A good name and a note on these Capture Layer Paint SOPs will help you and other riggers who venture in to your file know what you were up to.

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If you are using groups to do the capturing, it makes sense to also use complementary Visibilty SOPs and Capture Layer Paint SOPs for each group. Keep them in pairs. Keep the Visibility SOPs bypassed untill needed. When you are done painting that region, just bypass the Visibility SOP again and move on.

Visibility SOPs work great to getting paint interactivity with very dense skins. What you don't see doesn't get redrawn which is the primary slow-down when painting weights in Houdini 11 as the entire geometry has to be redrawn.

I always work with the SOP network when skinning geometry. Select the specific Capture Layer Paint SOP to work with in the viewport and do things that way and not rely on the viewport selection method. That's just me though, but I have seen ohter riggers in Houdini adopt this work flow to great effect.

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Visibility SOPs expect primtive groups while the Capture SOPs work on point groups. This means that your Group SOPs should capture primtive groups and then using the Edit > Convert tab to promote the primitive group to a point group and check Preserve Original to keep both groups around.

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You can hang off as many Deform SOPs as you wish throughout the capture chain. This allows you to quickly see what a certain set of SOPs are up to.

I like to hang a Deform SOP off the first set of Capture SOPs. Allows me to adjust capture pills without getting any painted weighting layered on top to see the raw capture.

All of this is completely up to you how you want to organize the skinning set-up in SOPs. It's pretty flexible if you keep things organized.

capture_prim_groups.hip

[hatrick]

Hi,

thank you very very much for such a detailed answer ... i ve used a basic autocapture sop and did a captureoverride for several pointgroups with operation set to "replace existing override". You re other workflow suggestions are also very helpfull !

greets

Lucas