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  2. Can I use the CHOP nodes to deform a line?

    Please don't take my advice as an offence The first 2 things you should do when leaning Houdini or any other software, is first learning the fundamentals by looking carefully the documentation and second practice by yourself. And not to bug this channel every second you get stopped.I also get stop 10 times a day, everyday since i start working a long time ago, and hopefull for everyone i don t post here Regards
  3. Today
  4. vector pos = point(1, "P", @ptnum); float mix = ch("mix"); @P = lerp(@P, pos, mix);
  5. Offset time on Copy to Points

    toadstorm, Thank you so much for the quick and in-depth reply ! I'm only a few months into this amazing Houdini/Vex thing, and I am still a beginner, but I have so much more understanding of these things than I did, thanks in part to the great information you put online. I have made an attribute based on the frameBorn att in my pops network that records the birth frame of each particle and then freezes on that number. I've never messed with stylesheets before, but I am going go through what you said step by step this evening to try it out. Thanks again ! I really appreciate the help. Not knowing this was giving me weird dreams. haha.
  6. In my Network view is a - hm, never recognized - background hint: "Profile 0: Time". What is it and how to dis/enable it?
  7. uvtexture camera preojection

    Seems like your geometry just needs more divisions. Here's the UVs from your original scene file: They look really distorted here. If the divisions on the larger box and the tube are increased, that distortion goes away:
  8. Uv textuer's camera projection donot work well. Dose anyone know way to fix?? Q.hiplc
  9. Yesterday
  10. Hello guys. I was wondering how to get the uv's from a rest position (time shift to frame 1) to a deofrming mesh. Otherwise my uvunwrap flicckers and calculates each frame which is not okay. Thanks a lot. P.D: Point number doesnt change.
  11. Offset time on Copy to Points

    Hmm... what you'd probably want to do here is start by creating an incrementing point attribute on your template points that represents what frame in the sequence you want each copy to load from. For this example, let's call it i@frame. Once you have that, you could create a string primitive attribute on your packed primitives (after the copy operation) that would point to the full path of the texture on disk: s@texture_path = sprintf("/path/to/textures/root/texture_%g.png", i@frame); Now that you have this as a primitive attribute, you could leverage material stylesheets to override the emissive texture (or whatever texture) on the material applied to your sparks. Stylesheets are a bit cumbersome to use in Houdini, but they're very powerful and they'll work with any render engine. Once you have a material assigned to your object, go to Inspectors > Data Tree > Material Style Sheets, then create a new stylesheet on the geometry container that your sparks live in. Then right-click the stylesheet in the Data Tree and "Add Style". You can then add a Target of type "Primitive", and then an "Override Script" of type "Material Parameter". Then change the "Override Name" column to the name of the parameter you want to override in your material... if you hover over the name of the material parameter in your shader network, you should see the parameter name. In your case it's probably going to be the emission color texture, which is "emitcolor_texture" in a Principled Shader. The "Override Type" should be "Attribute Binding", because you're using the attribute you created earlier to override the material value. Then set the Override Value to the name of the attribute you created: "texture_path". Your stylesheet should look something like the attached screenshot. Once that's done, if you render (and your material is set to be emissive, emissive textures are enabled, and your emission color is 1.0), you should see a unique texture applied to each spark.
  12. So I've investigated more tonight and finally I just don't have enough ram to fit the displacement calculation, even with 64 gigs i run short. I'll render the displaced ocean on a grid and the fluid itself on different passes and i'll make a bit of comp magic ! Cheers,
  13. [SOLVED] Displacement mask in shader

    Thanks a lot, it works ! Couldn't have figured it out without your help !
  14. setting attributes that stick

    Thanks guys, I looked at those links, very helpful. Thank you.
  15. I turned " Match P Attribute "on, but it doesn't work.
  16. I still was unable to get decent randomisation and i wasnt the only one. Another groomer had the same problem, so he made a tool to replace it.
  17. [SOLVED] Displacement mask in shader

    If you open up the Principled Shader with "Allow Editing of Contents", you have to look for a node called "displace1". The "scale" input of that node is where you put your mask. "Shift+7" shortcut will allow you to search for a node by name and highlight it.
  18. Add AOVs to ROP

    I recently did something like this but for a redshift ROP. What I did is that I just use the parm().set() function on that parameter, it acts just as a normal number parameter so you don't have to go the way of dealing with the whole getting a list of all the parms, adding an instance of a parm and then reapplying the new list of parms to the node. If you'd be interested you can have a poke at the shelf tool I made (assuming you are doing this with python): https://github.com/Underscoreus/Rs_AOV_Transfer Hope it can help
  19. [SOLVED] Vellum cloth attached to vellum hair issues

    no probs at all, if i throw enough darts...one might stick eventually.
  20. [SOLVED] Vellum cloth attached to vellum hair issues

    Sorry for bringing back this older thread, I just wanted to add a short addendum on how I was able to solve this issue in case others find them self in this pickle later on. So after some detective work, I found that the freakouts were caused by some constraints I had, attaching my vellum piece to a piece of deforming geometry (vellum attach to geometry constraint). If these constraints were not present the sim ran just fine. My substitute for these constraints were to simply animate my bottom piece to follow my deforming geometry using a point deform before configuring any of the vellum stuff and then when setting up vellum simply checking the "match animation" checkbox and setting the pin type to stopped. Then inside the vellum solver, using a pop wrangle to change the stopped attribute to 0 at a given frame to allow the sim to take over. One thing to be careful off when using this approach is that vellum creates an attribute called "fallback". I don't know what governs when it triggers and when it does not, but when it does, the sim will try to move your geometry back to the position described in the baseP attribute. For some reason it was triggering whenever my piece would hit the ground and the sim would try to send the piece back to the "rest" position. I simply solved this by adding another wrangle in the solver always setting "fallback" to 0 and it seems to have worked. Thanks for all the helpful advice given in this thread!
  21. Last week
  22. here is a simple example with Python, I attached an example: parm = hou.parm('/obj/geo1/sphere1/ty') # store all values in list values=[] for i in range(100): val = parm.evalAsFloatAtFrame(i) values.append(val) # remove parm expression parm.deleteAllKeyFrames() # set values from list to keyframes for i in range(100): myKey = hou.Keyframe() myKey.setFrame(i) myKey.setValue(values[i]) parm.setKeyframe(myKey) bake_keyframes.hipnc
  23. Hi ! I'm trying to replicate this tutorial : But i'm having trouble applying the displacement in the shader. It seems the tutorial was made with an older version of houdini and things have changed quite a bit since then. I managed to import the mask attribute in the shader but i'm stuck as to where should i put it. I did manage to do the displacement at SOP level but i'm lost in shader level... Any pointers ? Cheers ! pyrite.hipnc
  24. So after investigating more I think I have too much polygons and mantra crashes when calculating the displacement. The fluid is a poly soup with 2.4 millions points and I thought my computer will be able to render that easily. I turned off true displacement on the ocean shader and it's working nicely. Cheers, Edit : without true displacement, it's ugly as hell, and I've still not managed to fix the crash. If anyone has an idea about how to solve this, I'll be glad to read it
  25. Hey guys, I'm facing a problem when I want to render my extended ocean. Mantra crashes during the displacement creation process, and I'm pretty sure it's not an hardware issue (Ryzen 2700X, 64 gb ram). The output mesh is pretty bizarre : I have a surface created under the mesh when it should be flattened and so there should be no surface here : I dont know what's causing this, but I'm pretty sure that this makes mantra crashing everytime. I tried using a grid instead of the mesh and it's working. I think that what's causing this issue is that when I simulated the fluid there was no particle under the collider and so it results in this weird mesh, I'll try to simulate again with a larger particle layer to see if it solves something. Here are the meshing parameters : I can attach the file if needed but as there are heavy caches that needs to be calculated it may bothers when looking for the bug. Cheers,
  26. you CAN write the vex yourself every time if you want to, or if you feel lazy, just a Point SOP, preset Morph to 2nd input then you can have a controlled lerp amount.
  27. Offset time on Copy to Points

    That is really cool ! If you don't mind me asking, is it possible to use this on a PNG sequence to start the sequence from an attribute on each point ? Say I have animated a traditional spark and would like that sequence to be copied to points, and to play from it's first frame whenever a point has it's attribute changed or created ? I have been trying to find the answer to this for so long. I have learned several ways to do it with cached geometry, but just to apply it to a material/pngs I have been stumped for months. setprimintrinsic(0, "index", @ptnum, f@some_attribute, "add"); // this would offset the start of each copy by the value of f@some_attribute
  28. This seems to be a problem with the normals. If you add normals to the points with a normal or polyframe node before the copy to points they won't jump.
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