MarioD Posted March 17, 2017 Share Posted March 17, 2017 Hi, I'm pretty new to houdini so probably this is very basic.How can I control the direction of the wind field with the direction of an object?I hope someone can helpTks! Quote Link to comment Share on other sites More sharing options...
bloodhawk Posted March 17, 2017 Share Posted March 17, 2017 (edited) Get the Object Centroid. Get the velocity of that point. Now in the Wind Field DOP, under the direction parameters, read the velocity using a point expression for each of the respective axis. You can multiply that value by -1, if you want the Wind blowing in the opposite direction. Edited March 18, 2017 by bloodhawk Quote Link to comment Share on other sites More sharing options...
MarioD Posted March 18, 2017 Author Share Posted March 18, 2017 Tks, but I'm not sure I can do all that. I'm missing some basics. Can you upload a simple scene? Tks! Quote Link to comment Share on other sites More sharing options...
MarioD Posted March 18, 2017 Author Share Posted March 18, 2017 Ok I did it. Tks! But now I'm trying something a bit different. Now I would like to find the velocity of the faces of a rotating object. Then This object will be a volume that will control the amount of wind on a grass field, this part is working, I just need to be able to transfer the velocity vector of the poly faces to the wind direction. I think I'm almost there. I've attached a simple scene ObjectVelocity.hipnc Quote Link to comment Share on other sites More sharing options...
galagast Posted March 18, 2017 Share Posted March 18, 2017 Something like this? H16.0.550 Indie - ObjectVelocity_v2.zip 1 Quote Link to comment Share on other sites More sharing options...
MarioD Posted March 18, 2017 Author Share Posted March 18, 2017 Really cool, I still have soooo much to learn.... tks! Quote Link to comment Share on other sites More sharing options...
MarioD Posted March 18, 2017 Author Share Posted March 18, 2017 How can I pass that v value to a DOP's network wind velocity? Quote Link to comment Share on other sites More sharing options...
MarioD Posted March 18, 2017 Author Share Posted March 18, 2017 Im attaching my file. I want to use that object to control the wind force on a field of grass. A part of it it's working. I can affect the hair using the volume of the object and with your help I can get the vel. But I don't know how to pass that value, per point, to the Wind Velocity. CHOPS might be the solution, I've watched and read loads of stuff by now but I still can't figure it out. WindDirection.hipnc Quote Link to comment Share on other sites More sharing options...
galagast Posted March 19, 2017 Share Posted March 19, 2017 You can use a Sop Solver DOP to set forces for your points. H16.0.550 Indie - WindDirection_v2.zip 4 Quote Link to comment Share on other sites More sharing options...
MarioD Posted March 19, 2017 Author Share Posted March 19, 2017 Cool, so you replaced the DOP net that I had in the file? Quote Link to comment Share on other sites More sharing options...
MarioD Posted March 19, 2017 Author Share Posted March 19, 2017 (edited) I really appreciate your help, I'm studying what you did and most of it makes sense. Would be hard to get there alone with the knowledge I have now. Edited March 19, 2017 by MarioD Quote Link to comment Share on other sites More sharing options...
galagast Posted March 20, 2017 Share Posted March 20, 2017 9 hours ago, MarioD said: Cool, so you replaced the DOP net that I had in the file? More or less yes, you can still use the same setup inside the Guide Sim DOP instead, just add the multi-solver setup with the sop solver. Although I honestly haven't used the hair tools in Houdini yet, there might be other methods intended to do the same or similar effect 1 Quote Link to comment Share on other sites More sharing options...
MarioD Posted March 21, 2017 Author Share Posted March 21, 2017 (edited) Ok so, let me see if I understand. You used a SOP solver so you can use the Geometry (SOP level) to the simulation? Edited March 21, 2017 by MarioD Quote Link to comment Share on other sites More sharing options...
galagast Posted March 21, 2017 Share Posted March 21, 2017 Yup, something like that. In addition to giving access to all the SOP context nodes, the default nodes (dop import) contains the data of the current sim for you to freely process as you want. In the case of the above example file, I'm simply updating the force. I hope that made sense Quote Link to comment Share on other sites More sharing options...
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