Excuse the primitive questions…
I am creating some geometry via a Python script. There, to make it visible, I am assigning an attribute and set it to an arbitrary color, like this:
bla.setAttribValue(“Cd”,(0.25,0.5,0.0)) #green
Then, in Houdini, I do not seem to be able to change this color or assign materials. I think they get assigned but without any visible result.
Can you please advise on how to do this properly. I am obviously doing something wrong here…
Thank you.
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Technical Discussion » Assign material/color
- anna_waldon
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Technical Discussion » Unify polygon orientation
- anna_waldon
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Technical Discussion » Unify polygon orientation
- anna_waldon
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If I have a bunch of procedurally generated polygons (lying flat on xy plane) with normals randomly pointing to opposite directions, how can I unify them?
Thanks for the advice.
Thanks for the advice.
Technical Discussion » Procedural NURBS along polygons
- anna_waldon
- 52 posts
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Technical Discussion » Procedural NURBS along polygons
- anna_waldon
- 52 posts
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I reduced the number of points and the surface became smooth. So, I increased it back again and it does look angled in the viewport and smooth in the render. So, I am guessing it is a LOD setting somewhere? Also, the output of my Skin SOP is all black. Is it something to do with the normals oriented inwards (my guess from previous experience but I did not find Flip Orientation or similar)? It becomes OK after Convert SOP, but only if I convert to NURBS - polygons remain pure black.
I guess I need to educate myself about the geometry types in Houdini. They seem to be somewhat different that in other packages. I am not sure what the differences are between Mesh and Polygon types. And then there are some I have never heard of before. Pasted Surface, for example…
I guess I need to educate myself about the geometry types in Houdini. They seem to be somewhat different that in other packages. I am not sure what the differences are between Mesh and Polygon types. And then there are some I have never heard of before. Pasted Surface, for example…
Technical Discussion » Procedural NURBS along polygons
- anna_waldon
- 52 posts
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Thank you for the advice.
I did as you advised and am getting the conversion but the resulting surface still does not have continuity through points and consists of rectilinear patches. So, my problem remains – how, in this scenario, can I get a surface that is smooth in both directions? Sorry if I am missing the obvious.
I did as you advised and am getting the conversion but the resulting surface still does not have continuity through points and consists of rectilinear patches. So, my problem remains – how, in this scenario, can I get a surface that is smooth in both directions? Sorry if I am missing the obvious.
Technical Discussion » Procedural NURBS along polygons
- anna_waldon
- 52 posts
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Excuse further basic questions but…
I’ve done what you advised and have some progress (thanks again) but I am only able to get a ruled surface. It seems the Resample SOP outputs polygonal curves and not NURBS. I can use the Fit SOP after to fit a NURBS curve but this kills the purpose of resampling by producing crazy numbers of randomly positioned control points. I must be missing something obvious. How can I resample my profiles to have the same number of points each and skin them into a periodic shape (topological torus) that is smooth (NURBS) in both directions?
Thank you for the advice…
I’ve done what you advised and have some progress (thanks again) but I am only able to get a ruled surface. It seems the Resample SOP outputs polygonal curves and not NURBS. I can use the Fit SOP after to fit a NURBS curve but this kills the purpose of resampling by producing crazy numbers of randomly positioned control points. I must be missing something obvious. How can I resample my profiles to have the same number of points each and skin them into a periodic shape (topological torus) that is smooth (NURBS) in both directions?
Thank you for the advice…
Houdini Indie and Apprentice » Ramp-driven Scatter
- anna_waldon
- 52 posts
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Houdini Indie and Apprentice » Ramp-driven Scatter
- anna_waldon
- 52 posts
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I have a cylinder and want to distribute some points on it. One side needs to have more points that the other. Then I copy some objects onto these points. In some parts of the cylinder the objects need to be larger than in the others. I thought I would use ramps but I am struggling to find inromation/understand how to wire them properly to the appropriate parameters…
Thank you for the advice,
Anna
Thank you for the advice,
Anna
Technical Discussion » Procedural NURBS along polygons
- anna_waldon
- 52 posts
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Technical Discussion » Procedural NURBS along polygons
- anna_waldon
- 52 posts
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[postimage.org]
Thank you very much for the helpful answers (and patience)
No, of course not “convert”. I am aware that this cannot be clean. And, yes, I could rebuild this manually, in Houdini or elsewhere, but I would like to have a procedural solution so that I could produce variations by changing the parameters up the chain. I am actually not wedded to NURBS (but I think this is an interesting challenge because what I am trying to design here is a procedural-design workflow as much as an object) and my current model is actually smoothed (sub-ded) polygons but I would like to have cleaner and more rational output (this object is meant to be CAMed eventually).
This object needs to have straight, cylindrical inner surface, rounded transition edge and freeform outer surface. So, I was hoping that it might be possible to sample the outer part of the geometry at some regular intervals (I do not know, using ray casting, snapping with plane constraints or whatnot – this is where I am looking for advice). This would produce the points to draw the curves through. I would not care if the resulting NURBS surface is not absolutely precise. I could intersect these curves with the vertical curves distributed radially at equal intervals, fillet the intersections and get my profiles.
I am pretty sure I would be able to write a script for this, say in Maya or Rhino or elsewhere. So, I thought why not in Houdini (to which I am new but I hear what everyone says about the flexibility)? Obviously Maya and Rhino or engineering software do not provide metaballs and other parts of the workflow. Also, I like the visual programming approach and am interested to see how adaptable it is for my purposes…
Thanks again for your thoughts,
Anna
Thank you very much for the helpful answers (and patience)
No, of course not “convert”. I am aware that this cannot be clean. And, yes, I could rebuild this manually, in Houdini or elsewhere, but I would like to have a procedural solution so that I could produce variations by changing the parameters up the chain. I am actually not wedded to NURBS (but I think this is an interesting challenge because what I am trying to design here is a procedural-design workflow as much as an object) and my current model is actually smoothed (sub-ded) polygons but I would like to have cleaner and more rational output (this object is meant to be CAMed eventually).
This object needs to have straight, cylindrical inner surface, rounded transition edge and freeform outer surface. So, I was hoping that it might be possible to sample the outer part of the geometry at some regular intervals (I do not know, using ray casting, snapping with plane constraints or whatnot – this is where I am looking for advice). This would produce the points to draw the curves through. I would not care if the resulting NURBS surface is not absolutely precise. I could intersect these curves with the vertical curves distributed radially at equal intervals, fillet the intersections and get my profiles.
I am pretty sure I would be able to write a script for this, say in Maya or Rhino or elsewhere. So, I thought why not in Houdini (to which I am new but I hear what everyone says about the flexibility)? Obviously Maya and Rhino or engineering software do not provide metaballs and other parts of the workflow. Also, I like the visual programming approach and am interested to see how adaptable it is for my purposes…
Thanks again for your thoughts,
Anna
Technical Discussion » Procedural NURBS along polygons
- anna_waldon
- 52 posts
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How can I produce a NURBS geometry from polygons? What I have is a heavily distorted torus (actually, some walls might have holes, so complicating the topology but step by step) made by fusing metaballs. I then convert them into polygons to be able to cut out a cylindrical hole in the middle. I then want to have this (messy) geometry as well-organised NURBS. So, I thought I could intersect what I have with vertical radially positioned planes (or similar) generating points through which to draw my isoparm curves. I would then loft a surface through the curves, keeping it periodic in both directions. Keeping everything procedural, naturally.
How would I go about it? Does this sound feasible? Is this a good approach? I can make a couple of sketches if my description is unclear. Thank you very much for your advice!
Anna
How would I go about it? Does this sound feasible? Is this a good approach? I can make a couple of sketches if my description is unclear. Thank you very much for your advice!
Anna
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