Texture/Mask/Displacement Painting HDA, WIP

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Bennell
Hi Wout,

I've noticed six scales connected to each other on the mouth. Other than that, keep it up!


That's where the scales“ jump” to the close part of the mouth, fix is to do the scales on an open mouth model and then close afterwards, so shouldn't be a problem
Edited by Wout Tengrootenhuysen - 2020年10月19日 17:49:51
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If you're interested in ideas like regions and crease lines for your HDA, here's a paper.

Attachments:
RepTile.pdf (531.9 KB)

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Okay, thanks Bennell. I've got plenty to do for now, working on the sculpting mode of the HDA.
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I'm getting some strange full on hard crashes. I'm using the geo data parameter in a loop, to cache geometry after a brush stroke has been applied, and then that result is imported in a python sop and rrrrround we go. But Memory usage increases with every stroke up untill 99% and then sometimes it crashes, and it crashes hard, just screen flicker- back up corrupted-hard. If anyone has any ideas, that'd be very welcome

Thanks !
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Have you fixed your problem?
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Hey Bennel ! Yes I have , thanks for asking I sent a scene file to support and it as it turned out, there is a bug in Houdini versions prior to 18.5 where the geo stash parameter keeps track of ALL changes in the undo stack. That means everytime you overwrite the paramter , it is stored in memory, so that's why it crashed so often. It's been fixed in 18.5 and the solution for other versions is to clear the undos mannualy. I've switched to Houdini 18.5 now and fixed some things. It feels a lot smoother in general now
Edited by Wout Tengrootenhuysen - 2020年10月26日 08:48:35
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Great! How's the sculpting mode?
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It's coming along very nicely ! I've been doing some commissioned work so haven't really updated it in the last couple of days or so..
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When you have time, can you show how you did the scales on the iguana?
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Sure, in short:

viewer state for interaction, moving a point along a mesh
copy to points with said point and circle and attributes from viewer state
vex:
reproject onto mesh
finding intersections
cleaning up intersections( 3 posibilities, no points, 1 point or two intersection points)
create lines between cleaned up intersections
vex code for those lines: a behind test relative to center point of the circle and center point of intersecting circle
transform circles according to behind tested lines
vex : proximity check to only update points near the live point
vex reproject onto mesh

I've written some vex code to do extrusions, as the polyextrude often creates spikes, still have to implement that.
Also, performance wise, its not bad, but it does slow down quite a bit with a lot of scales. Looking into opencl to speed it up.

That's it in a nutshell
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How about bumps on a toad? https://upload.wikimedia.org/wikipedia/commons/3/39/Common_toad_%28Bufo_bufo%29_Kampinos.jpg [upload.wikimedia.org]
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Oh yeah, cool. That would already be possible with the current setup I think, by setting the intersection distance large enough so you can only draw “scales”/bumps when they don't or barely intersect, and then play with the extrusion setting to get a curvy bumpy look
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With your HDA, could scales and bumps be either geometry or displacement?
Edited by Bennell - 2020年10月30日 09:04:05
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Both actually, but I switched to developing the geometry side more because it became obvious that the poly count needed to create the fine detail for the scales would quickly become too much. But you can create geo with it or a heightmap to drive displacement ( not sure the last one will also be in V1.0 because it is much slower then geo and gives far less appealing results)
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Have you developed your HDA to the point where it can produce multiple types of scales?
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I'm working on that, I've been thinking about the different types: flat/sharp/ more protruded and extended…
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Sure yeah, should be possible already
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Can the HDA produce pores and wrinkles between them?
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I haven't thought about that, that would be some combination of geo and displacement perhaps..
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