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StopTheRain

Lacy texture from point cloud

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Hello,

 

 

I am trying to create lace-looking texture on a grid using positions of the points scattered on that grid instead of some UV-based noise VOP.

I use point cloud VOPs and distancePointToLine VOP to create a texture where each point is connected to its neighbors with one line.

And by changing search radius in pointCloudOpen VOP I can make it so that only close neighbors are connected.

 

It works fine for 3 points or for more then 3 points as long as they are equidistant.  

And I am getting lines overlapped sharply when I am using point cloud with somewhat random point distribution.

 

Could someone please suggest how to fix that or maybe use another way of connecting points other then with distancePointToLine VOP.

So that there is no sharp gaps where lines intersect.

 

 

post-8606-0-35343700-1412404795_thumb.jp

post-8606-0-07646400-1412404811_thumb.jp

lines.hipnc

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Still no luck. Here is another example with the same data of trying to connect points from point cloud file in shader. This time instead of using distancePointToLine VOP, direction of vectors is used: first - between 2 points of point cloud, second - between one of those point cloud points and shaded point. The final goal of those exersises  is creating some cool looking dynamic textures based on relatively sparse particle simulations. So far I am stuck at the base level of "connecting the dots".

post-8606-0-31718400-1412576300_thumb.jp

lines2.hipnc

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Hi Konstantin! Good to see you.

 

Here's my stab at it. It's a bit slower as it's in SOPs and rendering with actual lines.

 

I've also attached a more extensive use of this technique for creating pseudo languages. If you want to check it out. Full thread here: http://forums.odforce.net/topic/19945-alien-language-enginge/

post-1210-0-84847800-1412644153_thumb.pn

alienLanguage_11.hipnc

lines2_findshortestpath1.hipnc

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kleer001,

 

Thanks a lot for your reply. I certailny need to investigate possible use of findshortestpath SOP for what I am trying to accomplish. Though I am more after some sort of Delaunay triangulation for randomly distributed set of points, but not creating random shapes based on that set.  One thing I guess I am agree with you is that this could be easier (though slower) done in geometry context then in shader and then passed into shader afterwards. Particularly after seeing tutorial on cmivfx.com called "Houdini vein work". There is lots of VEX inline code in that tutorial instead of VOP networks, but results are looking somewhat closer to what I need to achieve

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I think the overlapping problem you're finding is because the VEX picks only one point to shade. And to get the smooth overlapping would require multiple samples, or a sample per point, which sounds kind of expensive too.

 

What size of point clouds are you working with? 100K 1.2M 32B ?

 

Also, I'm not entirely sure how well my SOP solution will scale into an animated scene. It might jitter a lot. Is your solution for animation?

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Animated source point cloud might be  in the range of millions of points. So far I have abandoned idea to do the whole transformation form set of points to texture in shader. Manipulating source points in SOPs and exporting the resulting point cloud for use in shader works better so far.

Here is static example of my source points and the texture that is created from them.  Possible  flickering due to the fact that source set of points is the result of particle simulation is a big concern now. Have not tested yet on sequence, but some sort of accumulation using SOP solver would be probably necessary.

 

post-8606-0-38565000-1412715007_thumb.jp

post-8606-0-88305000-1412715023_thumb.jp

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