thinkinmonkey Posted September 23, 2011 Share Posted September 23, 2011 Hi all, I'm transferring Cd attribute (but it can be any kind of attribute) from an animated sphere to a grid, as you can see in the attached file. Now, as you see, the red is transferred every frame, but we lose the red on previous "painted" prims. How can I still have the red on prims previously painted? In the file I propose a solution with the use of FILE SOP nodes, a simple trick: Houdini transfers the Cd Houdini saves the geometry (the last FILE SOP) Houdini goes ahead one frame Houdini loads the geometry saved on previous frame (the first FILE SOP), because the SWITCH SOP I put the FILE and SWITCH SOPs in bypass mode, because you have to choose the right folder where saving files. I'd like to know if there are other options. Thanks in advance. attribTransfer.hipnc Quote Link to comment Share on other sites More sharing options...
ehsan parizi Posted September 23, 2011 Share Posted September 23, 2011 (edited) You can do it in dops. with a sop solver. watch peter quint's tutorial on attribute transfer( http://vimeo.com/15923642 ), he explains it perfectly. Edited September 23, 2011 by ehsan parizi Quote Link to comment Share on other sites More sharing options...
symek Posted September 23, 2011 Share Posted September 23, 2011 (edited) There are two or three other choices. You need a time dependent context, which is Chops, Dops, Pops, but not Sops. Here you have a solution based on Dops (Sop solver). skk. ps note, sop solver can be applied on a geometry not involved in any simulation. It simply keeps a state of a geometry in a previous frame while executing current one. Edited September 23, 2011 by SYmek Quote Link to comment Share on other sites More sharing options...
spev Posted September 24, 2011 Share Posted September 24, 2011 (edited) If you open the houdini command line tools from the start menu (WIN) you can type proto_install. If you load the feedback node (follow the instructions) you will find that this node is a little simpler to set up (confusing to understand but simpler to set up), to achieve this exact effect. Please look at the example file..I hope this helps Edited September 24, 2011 by spev Quote Link to comment Share on other sites More sharing options...
spev Posted September 24, 2011 Share Posted September 24, 2011 Ooop here is the attachment feedBackNodeExample.hipnc Quote Link to comment Share on other sites More sharing options...
thinkinmonkey Posted September 24, 2011 Author Share Posted September 24, 2011 Guys, thanks for your answers, I'll give them a try ASAP. Quote Link to comment Share on other sites More sharing options...
ehsan parizi Posted September 24, 2011 Share Posted September 24, 2011 (edited) Hey Spev, that Feedback node looks neat! How can I read the documentation about it? EDIT : I found it, in command line, thanks for sharing this Edited September 24, 2011 by ehsan parizi Quote Link to comment Share on other sites More sharing options...
spev Posted September 24, 2011 Share Posted September 24, 2011 No worries dude....its been there for a couple of years and I am not sure why it is not part of the default package.....There is some talk on the forums about it and the command line help but that is all... It is a bit of a gem for when ever you want to accumulate data. 1 Quote Link to comment Share on other sites More sharing options...
ehsan parizi Posted September 25, 2011 Share Posted September 25, 2011 (edited) No worries dude....its been there for a couple of years and I am not sure why it is not part of the default package.....There is some talk on the forums about it and the command line help but that is all... It is a bit of a gem for when ever you want to accumulate data. Do you know if there's a way to animate before the feedback node?! for example in your file, how can we animate the point before the feedback node? when I wanna do it, looks like the feedback node ignore all the transformation that's happening before itself! EDIT : found my answer ....it was a matter of wiring the input geometry differently ... that's an awesome node, it's really weird that they don't have it as a part of the default package! Edited September 25, 2011 by ehsan parizi Quote Link to comment Share on other sites More sharing options...
spev Posted September 25, 2011 Share Posted September 25, 2011 (edited) In the messy (sorry) file I posted I was transforming the point with the first feedback node and the point node..This is probably why you trying to move the point was having no effect. In the attached example (more tidy) I am moving the point with a transform node...You can animate that point now until your hearts content....I hope this helps Edited September 25, 2011 by spev Quote Link to comment Share on other sites More sharing options...
spev Posted September 25, 2011 Share Posted September 25, 2011 Bugger...I will get tha hang of this attaching malarky one day!!!! feedBackNodeExample1.hipnc Quote Link to comment Share on other sites More sharing options...
spev Posted September 25, 2011 Share Posted September 25, 2011 Indeed ...Many an awesome node in Houdini! Quote Link to comment Share on other sites More sharing options...
ehsan parizi Posted September 25, 2011 Share Posted September 25, 2011 In the messy (sorry) file I posted I was transforming the point with the first feedback node and the point node..This is probably why you trying to move the point was having no effect. In the attached example (more tidy) I am moving the point with a transform node...You can animate that point now until your hearts content....I hope this helps hahaha...yeah, I figured it out. Quote Link to comment Share on other sites More sharing options...
Sifis Posted September 26, 2011 Share Posted September 26, 2011 If you open the houdini command line tools from the start menu (WIN) you can type proto_install. If you load the feedback node (follow the instructions) you will find that this node is a little simpler to set up (confusing to understand but simpler to set up), to achieve this exact effect. Please look at the example file..I hope this helps Man, this feedback node is awesome. I didn't even know there were so many prototype nodes waiting to be installed. Quote Link to comment Share on other sites More sharing options...
thinkinmonkey Posted September 27, 2011 Author Share Posted September 27, 2011 Ok, guys, thanks a lot for all your suggestions, I'll studied both and now I'm going to use what's best to fit for my project. ehsan parizi, SYmek: thanks for DOP solution. Just now I realized that only a solution based on simulation could be the only way, because it's in its nature to take in account the previous state in order to build the actual state, as SYmek pointed out. Of course, a BIIIIIG "thanks" goes to Peter Quint too! spev: thanks, man! For another time Houdini shows itself like a box full of toys ready to surprise you! Quote Link to comment Share on other sites More sharing options...
spev Posted September 28, 2011 Share Posted September 28, 2011 what would the feedback node in sop solver do? What would the feedback node in sop solver do? What would the feedback node in sop solver do? Quote Link to comment Share on other sites More sharing options...
thinkinmonkey Posted September 29, 2011 Author Share Posted September 29, 2011 I'm working on a road destruction: I'm using a moving-on-path sphere to select the primitives groups that have to be extruded and displaced. As you can imagine, because the sphere is moving, the primitives are taken only in the actual frame, forgetting primitives of the previous frames. So I thought to use some sort of mechanism to have the primitives of actual frame plus the previous ones "ready" for operations. Initially, I thouth to use attributes, but with the DOP solution, I'm saving a bgeo per frame with all the geometry and with a group that has all the interested primitives. I don't know if it's a good solution, actually it seems to work, but it's very slow, it has to check the distance for 458 primitive groups per every frame. Quote Link to comment Share on other sites More sharing options...
zarti Posted September 29, 2011 Share Posted September 29, 2011 not sure if this c'd help you in your case , but since i cannot have access to DOPs ( im an escapist ) some times ago i tried another primitive way of recording 'when happened to whom' events . basically a 'simulation' ( python SOP ) which writes to disc a txt file with two columns : indices & first-event-frame . those later are loaded as a single attribute back to the geometry . i saved and reloaded the geo with attributes in that case , but i think those c'd be read and applied from the txt file directly too . well .. i think =) you c'd save / load versions too if geo doesnt change its order or counts . link to the thread : the speed was greater without the printing to console option checked , but i activated it for the sake of the video . hope this suggestion helps . Quote Link to comment Share on other sites More sharing options...
Nik S Posted October 19, 2011 Share Posted October 19, 2011 On the Feedback Node, I load up the scene and the "feedback1" node is just get a merge node that is stuck in an Infinite Recursion... Am I missing something here? Cheers, =-N-= Quote Link to comment Share on other sites More sharing options...
thinkinmonkey Posted October 19, 2011 Author Share Posted October 19, 2011 If you open the houdini command line tools from the start menu (WIN) you can type proto_install. If you load the feedback node (follow the instructions)... Nik, have you done that? Quote Link to comment Share on other sites More sharing options...
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