angelous4x Posted February 29, 2016 Share Posted February 29, 2016 Hello everyone sorry if this is a silly question, i am still learning Houdini, coming from softimage. I love the attribute transfer node, but i am having a problem with the node. It might be me, but it doesn't seem to take or custom attributes. only global variables. I created a "blend" attribute to control the "distance threshold" within the attribute transfer node. but it gives an error saying "unable to evaluate expression(Undefined variable.. could I use a custom attribute in the attribute transfer node? Quote Link to comment Share on other sites More sharing options...
rich_lord Posted February 29, 2016 Share Posted February 29, 2016 I've been playing around with this node for a bit and I think the distance threshold is only run over once, meaning it can only have one value for all the interpolated points. It doesn't take custom attributes for me either. You can force one in there with a point expression - point("../attrib_create",@ptnum,"blend",0) but @ptnum always evaluates to 0, so it'll always pull the value off of point number 0. Kinda pointless. If you want to store a custom value for it, you might as well use a detail attribute and get it with a detail expression. I'm not exactly sure what you are after as you didn't upload your hip file. Does that answer your question? Quote Link to comment Share on other sites More sharing options...
angelous4x Posted February 29, 2016 Author Share Posted February 29, 2016 yess it does, thank you what i am trying create radiating rings from a point. so i wanted to use a sine wave and fit its range, to scale up then disappear. and off sent with the random start off value. Quote Link to comment Share on other sites More sharing options...
acey195 Posted February 29, 2016 Share Posted February 29, 2016 If you want to do this, you can do this inside a forloop, grouping the points by certain blend value range. If you are feeling more ambitious (and performance is an issue), you can attempt writing some vex (wrangles) for this, to create your own transferring node, not technically beginner stuff, but probably the best way to do this. (fastest cooking times, except for probably HDK nodes) Quote Link to comment Share on other sites More sharing options...
angelous4x Posted February 29, 2016 Author Share Posted February 29, 2016 interesting i'll try to for each loop, for me i wish houdini was a little more artiest friendly, there a few things i like to suggest form an general artist point of few, not a technical one. Quote Link to comment Share on other sites More sharing options...
animatrix Posted February 29, 2016 Share Posted February 29, 2016 You can implement this using pcfind_radius VEX function. But you have to implement your own filtering function because pcfind doesn't provide one unlike pcopen's pcfilter. Quote Link to comment Share on other sites More sharing options...
angelous4x Posted February 29, 2016 Author Share Posted February 29, 2016 damn, this is too beyond my knowledge. Quote Link to comment Share on other sites More sharing options...
rich_lord Posted March 1, 2016 Share Posted March 1, 2016 I had time to play around with this tonight and see if I could get it working. Using a foreach, I was able to have different blend values stored on the points that were then used by the attribute transfer sop. (good idea acey195) I set up the sine waves radiating after the foreach was done. I found it much more effective to use the blend attribute to control blend width rather than distance threshold, as its the gradient that I used to create the sine wave. Hopefully this helps - there was a bunch of stuff to set up on the foreach nodes. I think this is the simplest way you can get it to work though. Theres a few expressions I had to use to pull the correct data in. 16_02_29_radiating_sine_waves.hip Quote Link to comment Share on other sites More sharing options...
rich_lord Posted March 1, 2016 Share Posted March 1, 2016 Im sorry, I realsied I could animate the points, and I couldnt help myself rendering this little animation. I've attached another hip file with the animated point version. Its really simple, just some noise passing through them. 16_02_29_radiating_sine_waves_animated.hip 4 Quote Link to comment Share on other sites More sharing options...
angelous4x Posted March 1, 2016 Author Share Posted March 1, 2016 this is awesome!!!!!!! i did my own noob hack if you want to see it. I don't get the for each loop just yet, but i think this will help me out. closest_point.hip Quote Link to comment Share on other sites More sharing options...
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