ciappo Posted September 5, 2006 Share Posted September 5, 2006 Hi guys, here is a file and a video of an exercise that I'm trying to complete.. It is about splitting an image in small quads with the particle and then to rebuid the same image in a different shape... I found here some useful topics as for instance the flocking cones challenge, but there is one thing that I'd like to ask.. As you can see in the video my image is sliding on the quads and is not attached to them, because it's following the project uv sop that I used to map the image onto the grid generated by the small quads that are driven by the particles.. I tried with the rest position sop and vop, but i can't find the right way to use them... the fact is also that I'm not deforming an object but actually I'm reconstructing it by the copy sop, so actually I have many small objects that gives me my grid.. The video is not up to date, because the quads are not oriented, but you can see the problem about the image... So what do I have to do to keep the image on the quads??? Hope I was clear explaining myself.. Anyway, here are the file and the video... Thanks to everybody (I hope this is the right place for this topic...maybe wip would have been better??) imgParticle.mov imgParticle.hip Quote Link to comment Share on other sites More sharing options...
grasshopper Posted September 6, 2006 Share Posted September 6, 2006 Pietro, Check out this hip to see if it helps you. I'm sticking my neck out a little as I only had ten mins spare to spend on this so it is very rushed! Basically you need to add your UV's to the rest state and copy the uvs to the geo after the sim. If you do it your way you are always projecting in the same direction even if the pieces are rotated so the uv's don't "stick". As I was in a hurry I just used another POP network and a copy to get me the rest geo I needed. This is slow and I'm sure you can find a better way but hepefully you'll be able to see what is needed. I may take another look tomorrow if someone else doesn't jump in. Oh I also cleaned up your POP network a little to simplify it!! Regards, John. imgParticle2.hip Quote Link to comment Share on other sites More sharing options...
ciappo Posted September 6, 2006 Author Share Posted September 6, 2006 Hi Grasshopper, Thank you so much!!!! It is exactly what I was looking for!!!!! You're right about what was the problem, I knew that I was continuously projecting my texture but I didn't know how to avoid that.... What you did is great, now I know also how to use the texture in the point sop. I really love Houdini for this kind of solutions. Thanks for the POP network too, I'm really new to particle system, and I'm still trying to get my mind around them.. I substitute the pop network you copied with the same chain that I used to attract the particle, the add sop that copies the points in the middle of the prims of the base_grid. Is this a good way to solve it ? Or you suggest something different?? Thanks so much again!!! This makes me understand a lot of other stuff !!! Now I have to find a way to fix other stuff in this file like the rotation of the quads on the bent grid.. here is the file if you want to have a look...I used a tube as goal so it's clearer the result that i was looking for Cheers pietro. imgParticle3.hip Quote Link to comment Share on other sites More sharing options...
grasshopper Posted September 6, 2006 Share Posted September 6, 2006 Pietro The copying points to prim centers works great. Much better than the POPs thing I did. Anyway, here's another hip with a pretty hacky solution for getting the final shape formed correctly with the pieces rotated the right way round. It's really nothing more than a simple morph of the target geometry and the quads. This fixes the rotation issues and also stretches the quads into the correct shape to fit together properly. The sorts are needed so that the points are reasonably close together before the shapes are blended otherwise it looks nasty (and gives away the hack!). Now see if you can get it working on the tube! john imgParticle4.hip Quote Link to comment Share on other sites More sharing options...
ciappo Posted September 6, 2006 Author Share Posted September 6, 2006 Hey Grasshopper, you're amazing, I'm having a lot of fun... Here is the 5th file with the tube, but I want to point out two things... 1.If you're not going to blend the textures, you don't need the project and the material SOPs before the sort 2 SOP, because we have the rest position copied... right?? In this way I nedeed to get the number of prims of the tube propotioned to the number of prims on the grid_base...With blending the texture you just need to adjust the projection on the tube..right?? In the file there are both solutions.. 2.I saw that the problem about the "later adjustement" of the texture in your file is because actually the particle are not still there so they still have some velocity e by this they drive the orientation of the already blended points...right?? I want to thing about a solution for this now...maybe is going to take me years.. Sorry for my questions, but it is just because I'm guessing.... lot of new stuff for me.. You're helping me a lot... Cheers pietro. imgParticle5.hip Quote Link to comment Share on other sites More sharing options...
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