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  2. Smoke flickers when thin

    This is a WIP, I can't figure out why the smoke starts flickering towards the end when it thinner. any suggestions? A_exposion_03.mov
  3. Dot Vector in Python ?

    Common I missed that. I suppose my truncated rounded variable is not working as I thought, if it was the results should be match
  4. Today
  5. Advecting POPs with a Velocity Field???

    wrong section.
  6. There is a swiss cheese example in the docs which does exactly what you are after, at the bottom of the page. http://www.sidefx.com/docs/houdini/model/looping
  7. Yesterday
  8. Spyrogif

  9. Hey all, doing some chops studies here. I would like to use a channel I have created in chops (jitter) to drive the scale parameter within a jitter node. (See attached--red backdrop). I believe I have everything set up correctly, but apparently I cannot just plug in the attribute jitter, or its channel name, to get the desired affect? And this is despite the fact tha I can see the jitter float attribute in the geo spreadsheet behaving the way I want it to. What gives? Looking through some stuff on Tokeru (love that site!), I noticed that when chops are used to drive attributes, it is often to drive ones that exists already, say a channel called zscale being applied to zscale in an extrude later downstream. Is this the way you have to do this? Or maybe I am missing something very simple. Thanks! chop_studies.hipnc
  10. Modify Result Of Instance Geometry?

    As I know, only viewport and rendering process have capability to evaluate instance node.
  11. Forgive a beginner's question, but I'm trying to create a branching effect with particles that looks like data visualisation. Please see attached jpg for a crude drawing of what I'm after. I'm planning to emit points upwards from a surface, then have them clump together into one stream, then separate out again into branches before finally flowing into an animated chart / graph. I've done some initial tests with pop attract and found it really hard to use as the particles kept overshooting and bouncing back and forth, not really landing on the target. Any pointers in the right direction is great appreciated, many thanks!
  12. motion vector pass for Nuke

    You don't have to do conversion from space to space for getblurP nodes. Check documentation about that node. You have also example in documentation with this
  13. Dot Vector in Python ?

    You are missing a closing parenthesis at the end of dot = hou.Vector3(primColor).dot(hou.Vector3((rounded))) -b Too late
  14. Dot Vector in Python ?

    def theLooper(curNode): for thePrim in curNode.geometry().prims(): primColor = thePrim.floatListAttribValue("Cd") rounded = tuple((round(total,3)) for total in primColor) print(thePrim.number()) print(primColor) print("Theese are the rounded numbers\n"+str(rounded)) #print(round(primColor,3)) dot = hou.Vector3(primColor).dot(hou.Vector3((rounded))) # closing parentheses was missing tolerance = 0.000001 if dot >= 1.0-tolerance and dot <=1.0+tolerance: print("match") else: print("no match") if curNode.geometry().findPrimAttrib("Cd"): print("yes") else: print("no") Python tends to throw a syntax error on the following line when a line doesn't complete it's statement i.e. parentheses block not closed.
  15. Dot Vector in Python ?

    def theLooper(curNode): for thePrim in curNode.geometry().prims(): primColor = thePrim.floatListAttribValue("Cd") rounded = tuple((round(total,3)) for total in primColor) print(thePrim.number()) print(primColor) print("Theese are the rounded numbers\n"+str(rounded)) #print(round(primColor,3)) dot = hou.Vector3(primColor).dot(hou.Vector3((rounded)) tolerance = 0.000001 if dot >= 1.0-tolerance and dot <=1.0+tolerance: print("match") else: print("no match") if curNode.geometry().findPrimAttrib("Cd"): print("yes") else: print("no") The error is at the `tolerance` variable ?
  16. Houdini Expression Editor plugin

    Great thanks a lot. This should be doable no ? I'll look into the code
  17. Hey there odforce! Right now I'm trying to do a destruction simulation on a spaceship that I made, and I'm running into a problem that I can't seem to figure out. If anyone is familiar with Steven Knipping's Rigids III, the general setup is based off his approach. Here's some quick info on what I'm doing: * I'm simulating the spaceship destruction with bullet/packed primitives * These packed prims are a mixture between voronoi shattered pieces and unshattered geo pieces * Even when the spaceship is standing still, forces on the constraint prims will reach infinity once simulation begins * In DOPS, I've made a SOP solver that breaks my hard constraints once it reaches a certain force threshold, and since things are reaching infinity, it's basically just destroying all my hard constraints within a few frames Here's the ship: Here's the constraints using connect adjacent pieces from surface points with default values: After a few frames of simulation, it turns to dust =/ In dops, force is shown to reach inf and breaks the constraints based off my attrib wrangle which says... f@superHighNum = 100000000; if(f@force > f@cat_hard_break_force && f@cat_hard_break_force < f@superHighNum){ @group_broken = 1; } where f@cat_hard_break_force is the force threshold that I define I tried countering this behavior by adding the f@superHighNum, but it looks like forces gradually reach infinity, so it still breaks... Has anyone encountered this sort of issue before? If so, what might cause these forces to reach infinity? Here's a few things I've tried: * Cleaning up the mesh and fusing points before connect adjacent pieces * Setting rest length to zero * Blasting funky looking constraints before simulation * Trying a bunch of different settings on connect adjacent pieces when generating the constraints * Simulating with glue constraints to see if forces still reached inf (they do not reach infinity with glue) * Increasing the constraint force mixing parameter * The RBD physical properties are at default values Also be sure to check out Steven's tutorials because they're really awesome. I couldn't find his e-mail to ask about it, but perhaps you guys might have some ideas? Any thoughts, theories, ideas, would be greatly appreciated, thank you for your time! - Tyler ssGainz_v011.hiplc
  18. Parenting at geometry level

    I just wanted to know if something similar to parenting existed in the same way at geo level. Apparently not. So I guess I can certainly do it with a hierarchy of objects.
  19. I found this post while looking for best Houdini - Mari workflow practices. I didn't see any responses so I'll try my best to respond but this might not be 100% correct. First if using UDIMs make sure that you are using filename%(UDIM)d.ext. In the video at least when I went back to look at it you didn't have the %(UDIM)d but were using $F which unless it has changed in newer versions of Houdini won't work. Also don't forget in MAT context you need to bring in a uvcoords node, plug that into your texture node and then you can plug the texture into the shader. To go over the "simple" Principled shader first you would want to have maps for A. A color map for the base(diffuse) color. This is the outer layer of the skin but light is not passing through. B. A Color map for the Subsurface Color. The color that is under the skin or the meat. C. A Scalar map that will drive the subsurface amount. Where the skin should allow more and less light. D. Specular(Roughness) and Displacment maps would work like they always have. The Skin Shader is pretty much this same process but it allows up to three layers of skin shading instead of the one that is the subsurface color. So for each skin layer you want to use A. A color map for the skin layer. B. A Scalar map for the weight channel. 0 no subsurface color 1 all subsurface color. Just because you have 3 skin color channels does not mean you have to use all 3. The skin shader will work fine with 1 or 2 skin layers and the ones you don't use the weight turned to 0. The advantage of the skin shader is that you have a scattering distance for each color channel. I think for the veins you painted you would want some of them to appear on the base color, and some to appear as part of the subsurface layer but not as a separate scattering layer. Some veins are very close to the surface more appear as someone gets older and those would probably best be a part of the base color. Others are deeper so they don't easily appear on the surface. In Mari if you have the veins painted as a separate layer you could copy the veins into different channels and maybe mask or adjust the colors so that more or less appear across the body in the different render channels. Some links on rendering skin. http://gl.ict.usc.edu/Research/DigitalEmily2/ http://www.anderslanglands.com/alshaders/tut_skin1.html https://www.fxguide.com/featured/pixar-deep-dive-on-sss-siggraph-preview/
  20. The Cube

    looks interesting, like some sort of thing inspired by transformers
  21. Sand Simulation

    Hi! I'm a student at NAD in Montreal and I'm trying to learn Houdini. I have a project in which I need to simulate sand on top of a falling rocks RBD simulation, which is on top of a FEM sim. (The FEM is the deforming ground) So I cached every collision objects with the CollisionSource node (with 4 substeps to match de grain solver). Now, if I simulate the sand, it explode on random frames. (see flipbook here: password: sandsim This is my second attempt and it still explode (at fist I used 10 substeps) Does somebody have any ideas on what could be the issue? Thanks MountainGrowth_47.hipnc
  22. Torus Procedural

    Images you attached are probably generated by some mathematical software like Wolfram Mathematica or MatLab. So if you have exact math function for generating those you can use them in Houdini too. For such Math approach (not really procedural in manner of combining full potential of Houdini), you can use ISO Surface node. Basically that node will accept any function of X,Y,Z coordinate in implicit form. For example if you want to define surface of sphere with radius 1. You actually thinking of function which will give you all points which are at exact 1 unit from let say center of scene. Function which cover that in 3D space would be sqrt(x^2+y^2+z^2)=1 If x,y,z represent coordinate of point then any point with such x,y,z that satisfy equation will be at surface of that one unit sphere. Making power of 2 on both sides of equation of unit radius sphere gives you x^2+y^2+z^2 = 1 That is explicit form of function. If you transfer right part to left: x^2+y^2+z^2- 1 = 0 Now when right part is 0 it could be removed (but think on it as if it exists and is equal to zero) and it leaves you with implicit form of equation x^2+y^2+z^2-1 and that example is default expression value in ISO Surface node. Unit length sphere. That node samples 3D space in ranges you set and for any point in that range generate surface (iso surface) if point's coordinates ($X,$Y,$Z) satisfy implicit equation you entered. Equation of simple torus in implicit form would be (R - sqrt(X^2 + Z^2))^2 + Y^2 - r^2 where R and r are large and small radius of torus ISO_torus.hip Without proper formulas for exact definition of your surfaces everything else is just guessing. If that is good enough you can try modify equation. Btw. any kind of function can be processed even something like noise($X,$Y,$Z) Doing proper math for repetition of many radius levels involve some of repetition functions like Modulus or trigonometry sin or cos. Rearranging arguments for solving for small r gives r = sqrt((R - sqrt(X^2 + Z^2))^2 + Y^2) replacing that instead of r in original function gives you 0 because any point doesn't matter of its coordinate satisfy equation, but if you expand that expression like this r = int(N * sqrt((R - sqrt(X^2 + Z^2))^2 + Y^2)) / N you actually quantize only those points which match quantized radius satisfy equation. ISO_torus_repetition.hip As you can see in example you can also use logical function to clamp calculation in some segment. Expression length($X,0,$Z)<R clamp calculation only inside tube of radius R. That example gives your image 1 On image 2 and 3 you can see that changing over Y axis bends toruses. so you have to put that in equation etc. This is NOT procedural approach, it is just pure math of surface representation for some equation and since you have images from Math software I suppose you also have exact function so you can use it on the same way in Houdini.
  23. Subfracturing in a SOP Solver

    works for me. was able to play the whole framerange without any trouble (H16.5). Edit: H16 does crash for me too
  24. ah i have 293. I had a heck of a time getting my license installed, would not connect to license server etc. lotsa email help from support.
  25. Is there some special reason for doing boolean in each iteration? If you only need holes on your sphere there is no need to use FOR loop since CopyToPoints node already do iteration. It's just about thinking. Instead to bool with each box, you can first create whole geometry for bool difference (stamping cubes all around) and then you use single bool node to make subtraction against sphere. Boolean.hip
  26. Subfracturing in a SOP Solver

    I need some suggestions on how to fracture an existing RBD object inside of a SOP Solver. The two solutions I've tried so far crash after a couple of fractures. All it is is a ball floating around and when ever CHOP network returns a value of 1, each piece of the ball splits into two smaller pieces. For those interested in how I'm currently doing it, I've got my RBD object plugged into a multi-solver, with the Rigid Solver in slot 0 and the SOP Solver in slot 1. Inside the SOP Solver there's a switch that reads some data from a CHOP network. If the result is not 1, then it just puts through the existing geo, if its 1 then it (tries to) fracture the object. My current solution is to unpack the object, scatter points and voronoi fracture the object, assemble the object, transfer all attributes except for name and id from the piece being fractured, and then give each piece a unique name. This kinda sorta works except for the fact that after a few fractures it just crashes. CPU and RAM usage are basically nothing, it just seems that I've done something wrong and Houdini doesn't like it. dancing_sphere_odforce_v1.hipnc
  27. in some circumstances I dont see my constraints anymore... especially if I work in the sopsolver. They are still functionally but thats it.... Any Idea? ahh: 16.0.633 is my version and the graphicdrivers are ok.
  28. This was fixed in a recent build.
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