dangerweenie Posted October 17, 2011 Share Posted October 17, 2011 Hi, Does anyone know how to get a Group Geometry node to update what points fall within it's bounding volume for point selection? Or even better - can anyone recommend a good way to create a volumetric "mask" (ie metaball, sphere, cube ... any simple geo) as an input for a nonlinear deformer (mountain SOP, wave, etc) being applied to a mesh? Something with falloff would be awesome, but I can't be too picky. I know this is a very common technique in Houdini, but I'm having a really hard time finding any info on it today. File is attached. Thanks, Matt falloff_question.hip Quote Link to comment Share on other sites More sharing options...
ehsan parizi Posted October 17, 2011 Share Posted October 17, 2011 Hi, Does anyone know how to get a Group Geometry node to update what points fall within it's bounding volume for point selection? Or even better - can anyone recommend a good way to create a volumetric "mask" (ie metaball, sphere, cube ... any simple geo) as an input for a nonlinear deformer (mountain SOP, wave, etc) being applied to a mesh? Something with falloff would be awesome, but I can't be too picky. I know this is a very common technique in Houdini, but I'm having a really hard time finding any info on it today. File is attached. Thanks, Matt the bounding volume in group geometry sop?! Quote Link to comment Share on other sites More sharing options...
dangerweenie Posted October 17, 2011 Author Share Posted October 17, 2011 Hey, I've got that setup (in the example file I attached) .... however it does not update every frame. (The bounding volume input is animated). Do I have to use a SOP solver? I don't know how. Is there an easier way? the bounding volume in group geometry sop?! Quote Link to comment Share on other sites More sharing options...
ehsan parizi Posted October 17, 2011 Share Posted October 17, 2011 (edited) it's not updating because you're using points of your group instead of your group name. Take a look at the attached file, it's updating now. IF you wanna keep the deformed parts deformed, even when they're not inside the group anymore, you can use sop solver, but other than that you don't need a sop solver. falloff_question.hipnc Edited October 17, 2011 by ehsan parizi Quote Link to comment Share on other sites More sharing options...
dangerweenie Posted October 17, 2011 Author Share Posted October 17, 2011 DERP! thanks man! Do you have any recommendations for pulling something like this off that has some falloff? Like the way a metaball can have a heavier weight towards the center of it's volume? it's not updating because you're using points of your group instead of your group name. Take a look at the attached file, it's updating now. IF you wanna keep the deformed parts deformed, even when they're not inside the group anymore, you can use sop solver, but other than that you don't need a sop solver. Quote Link to comment Share on other sites More sharing options...
ehsan parizi Posted October 17, 2011 Share Posted October 17, 2011 DERP! thanks man! Do you have any recommendations for pulling something like this off that has some falloff? Like the way a metaball can have a heavier weight towards the center of it's volume? hmmmm... depends on what you want to do. Attribute transfer might be the answer! Quote Link to comment Share on other sites More sharing options...
dangerweenie Posted October 17, 2011 Author Share Posted October 17, 2011 attribute transfer from the metaball weight to the vertices of the group input bounding geo? if one converts a metaball to points, could one use that with the weight attrs intact? How would you scale the effect of say, a mountian deformer, based on the part of the volume? Centroid expression? :/ Thanks for the reply! hmmmm... depends on what you want to do. Attribute transfer might be the answer! Quote Link to comment Share on other sites More sharing options...
ehsan parizi Posted October 17, 2011 Share Posted October 17, 2011 attribute transfer from the metaball weight to the vertices of the group input bounding geo? if one converts a metaball to points, could one use that with the weight attrs intact? How would you scale the effect of say, a mountian deformer, based on the part of the volume? Centroid expression? :/ Thanks for the reply! I didn't use metaballs for this. Maybe metaball gives you a simpler solution, but that's how I made it. I also couldn't make mountain sop use the $SMOOTH attribute, so I used an anti-aliased noise in VOP SOP. falloff_question3.hipnc Quote Link to comment Share on other sites More sharing options...
ehsan parizi Posted October 17, 2011 Share Posted October 17, 2011 (edited) this second file is more similar to a mountain sop ... I think I did something wrong in this one, just ignore this second one for now UPDATE : if you disconnect the point normal inside the vop sop that would work just fine falloff_question4.hipnc Edited October 17, 2011 by ehsan parizi Quote Link to comment Share on other sites More sharing options...
dangerweenie Posted October 17, 2011 Author Share Posted October 17, 2011 Hey, Thanks so much! This is pretty sweet ... checking it out now. I'm still pretty new to Houdini, but it seems like the VOP SOP that you used in this example is pretty similar to the Mountain SOP (you mentioned they would look similar)- are they using pretty much the same (VEX?) code? Thanks! Matt this second file is more similar to a mountain sop ... I think I did something wrong in this one, just ignore this second one for now UPDATE : if you disconnect the point normal inside the vop sop that would work just fine Quote Link to comment Share on other sites More sharing options...
ehsan parizi Posted October 17, 2011 Share Posted October 17, 2011 Hey, Thanks so much! This is pretty sweet ... checking it out now. I'm still pretty new to Houdini, but it seems like the VOP SOP that you used in this example is pretty similar to the Mountain SOP (you mentioned they would look similar)- are they using pretty much the same (VEX?) code? Thanks! Matt I'm not sure if it's the same VEX code, but it sure does look similar Quote Link to comment Share on other sites More sharing options...
ehsan parizi Posted October 17, 2011 Share Posted October 17, 2011 One more thing that you might wanna do is that, instead of using a polygon sphere, for your sphere2, use primitive sphere, that way you get a better result with attribute transfer and don't need 2 attribute create nodes, and you can either only use your $CR inside the VOP SOP and the change the color, OR make only 1 attributeCreate node. you can see the difference between them in attribute transfer node, change the sphere2 node type from polygon to primitive, and also increase the threshold in attribute transfer. it looks like when you use a polygon, just points or maybe surfaces are affecting the geometry that we want to transfer the attribute to (first input) but with primitive type, you get the whole volume. Quote Link to comment Share on other sites More sharing options...
dangerweenie Posted October 25, 2011 Author Share Posted October 25, 2011 Thanks Ehsan! One more thing that you might wanna do is that, instead of using a polygon sphere, for your sphere2, use primitive sphere, that way you get a better result with attribute transfer and don't need 2 attribute create nodes, and you can either only use your $CR inside the VOP SOP and the change the color, OR make only 1 attributeCreate node. you can see the difference between them in attribute transfer node, change the sphere2 node type from polygon to primitive, and also increase the threshold in attribute transfer. it looks like when you use a polygon, just points or maybe surfaces are affecting the geometry that we want to transfer the attribute to (first input) but with primitive type, you get the whole volume. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.