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  2. I did offset the points along the Normal direction to fix the inaccuracies of the Ray test intersection and all is working now thanks again Ioannis ray_project_cull_self_offset.hip
  3. You just need to introduce a little ray bias into your Ray SOP. A value of 0.1 got me pretty close. If all you're trying to do is remove points that are backfacing the camera, there's a simpler way. Unique the points on your mesh using a Facet SOP or however you like, create point normals via a Normal SOP, scatter, then just use a Delete SOP in Normals mode. There's an attribute there that accepts a camera input to determine backfaces. As long as the scattered points inherit your mesh's point normals, this will work.
  4. Yesterday
  5. Hi Henry, Thanks a lot for the file it is working fine as long as the points are based on different geometry when i use the same object to construct the points there are a lot of inaccuracies normally all the points that are facing the camera should be visible please have a look at the file Thanks in advance.Ioannis ray_project_cull_self.hip
  6. take a look at this file... it's using a Wrangle to create the projection vector to the origin for each point, and a Ray SOP to actually do the projection. ray_project_cull.hip
  7. Hello to all, this is my first post I am starting to learn houndini i try to convert some of my projects done with grasshopper i want to do a line mesh intersection test to cull points that are behind a mesh obstacle for each point i need to create a line to the camera origin and then check if the lines intersect with the mesh if true then i need to remove those points Any suggestions ? Thanks in advance. Ioannis
  8. Dynamic constraint network creation

    https://sidefx.com/tutorials/houdini-dynamic-fracture/
  9. use v@scale, it's built into the copy SOP
  10. Houdini Book?

    Found it on the sideFx website, seems like it just moved to a new spot on the site https://www.sidefx.com/tutorials/softimage-to-houdini-transition-guide/ direct link https://www.sidefx.com/media/uploads/tutorial/jordi/softimage2houdiniguides_all.pdf
  11. Intersection with primitive along vector

    yeah sorry it wasn't a direct answer coz I'm not a VEX expert myself...but I was hoping that would provide you with a spark with the thought process, it did !!!
  12. Hey all, I am looping a piece of geometry along a curve, and am controlling the scale of each copy using @pscale --itself being controlled via a ramp Is there any way to increase the functionality of pscale so that I can scale the object separately in the x and y axis? id like to have control over the x and y scaling parameters separately if possible. ive attached a scene file. Thanks! Modeling_Ramps_upl.hipnc
  13. duhhh, forgot to attach file. prev_P_example.hip
  14. might be some details lost in your exact setup? hard to tell without a HIP. here's a working example.
  15. Just wanted to add a quick something to this: you can actually access another input's attributes without having to use the point function. Appending opinput# before the attribute allows you to designate which input to access. v@opinput1_P would access the second input's P attribute for instance. So you could actually get the distance with a single line f@dist = distance(@P, v@opinput1_P);
  16. Intersection with primitive along vector

    Okay, I figured it out. It was because for some calculations the point was past the point of the dir vector, so it just returned 0 because I assume it wasn't 'long' enough. I multiplied it by 10 and it works fine now
  17. I am currently using a sop solver to update the position the position of some points based on the current position. I need to save the current position as a new attribute to calculate the distance between the new position and the current position. My approach was to save the attribute out before I do the calculation, so that each position will be saved as an attribute before the calculation. However, the doesn't seem to work I did : v@prevPos=@P; my calculation which is v@P+=@V*timestep; v@nextPos=@P; as you can see, the @prevPos in frame 2 should equal to @P in frame 1, but it doesn't?
  18. Ray node scale input

    It should work if you write @Cd into the Scale parameter.
  19. Intersection with primitive along vector

    Yeah, I used intersect() and it works fine but, I assumed that &p: int intersect(<geometry>geometry, vector orig, vector dir, vector &p, float &u, float &v) would write out the point of intersection between the ray and geometry. For me, it just copies @P (orig vector) giving me the points position as the intersection point which clearly doesn't make sense. Did I understand it wrong? edit: I changed the orig vector to something else and &p gives me the orig vector every time? The dir vector is (goal - orig)
  20. Animated loop in particles?

    To answer your question specifically, to replace particles with animated geo -- copy your animated geo onto your particles, and if your particles are already looped, make sure your animation cycles of your geometry match the duration of your particle animation and youre done! Keep in mind the fundamental use of the sin wave -- it is super functional for creating loops in all types of animations
  21. Group combine pattern syntax

    In your copy transform output copynum attrb pack your geo then you can use the the module function in a prim wrangle to get every 2 prim grp if(@copynum % 2 == 1){ i@group_newGrp = 1; } You could also use the group range as well.
  22. Group combine pattern syntax

    Hello ! I’m completly lost with group syntax and wildcards. I try to combine every second primitive group. Looked at the doc (http://www.sidefx.com/docs/houdini/model/groups.html#syntax) but it doesn’t help me sadly. Any advice ? Thanks group_problem.hip
  23. Animated loop in particles?

    You can use the Make Loop shelf option from the Game Development Toolset shelf. Dive inside it to see how it is made so you can modify it yourself.
  24. Environment variables question.

    To launch in manual you need to use a flag on starting Houdini executable file. This is a bit easier in the command line, link below, as you only need to add the -n flag. If you launch on windows via the desktop you can edit the shortcut launchers path and insert the -n in there. http://www.sidefx.com/docs/houdini/ref/commandline.html As for the save incrementally. It depends on what you mean by that. Houdini by default allways saves a backup every time you save. If you want in the preference you can turn on auto save over a certain time period. If you want it to numerically change the version number of the scene, you can make a simple python script that does it and you can place it in numerous locations that you see fit. So I can answer that one depending on what you are looking for.
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