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Everything posted by trzanko

The copy to points node accepts an orient quaternion and also a vector "matrix" as @N for zaxis, v@up for yaxis, v@side for xaxis. if these are packed objects you can set the transform primintrinsic to a matrix3 comprised of the v@side,v@up,@N matrix

use a sop solver to accumulate an attribute over time, it's not just age or time it comes in handy for a lot of things like rotating particles based on how far it's traveled

you're also able to change the space the motion blur happens in using the transform vop. so if you want 3d moblur you should use world space and if you want 2d moblut transform to NDC space

No matter the orient or resolution of the wires you can determine the point nearest the surface. You can use the vertex prim index function to determine which points are the 0 point on the primitive. http://www.sidefx.com/docs/houdini/vex/functions/vertexprimindex Then if the points that equal vertex zero are actually the furthest from the surface you can determine how many points are on the primitive by the prim vertex count function and then the point that has that corresponding vert number is the nearest point. http://www.sidefx.com/docs/houdini/vex/functions/primvertexcount Furthermore if you have varying wires where the nearest point is sometimes the zero point and sometimes the end point then you can determine which one is closest to the skin by measuring the length to the nearest point on the nearest primitive. Hope this helps, Tighe

Nice! Let me know when it's finished, excited to see the final result!

You can use an add sop and connect by attribute and enter "id". as long as there are proper id's they'll connect

connect the floor points to the foot points by an id and then manipulate those curves?

This tutorial goes over from start to finish the creation of a rudimentary fence asset that can easily be expanded upon. This is an introductory lecture on procedural modeling in Houdini I gave at Drexel University's SIGGRAPH chapter as a Junior Animation & FX major. Let me know if you have any questions, enjoy! Link To Demo File: drive.google.com/open?id=0BRBrg9uoWkNDU2ZUYnFpUjQ Link to Documented File: drive.google.com/open?id=0BRBrg9uodEhVYnluaFRGeGs
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 procedural modeling
 fence
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Yea absolutely! Excited to see how much attention it got, seems like procedural modeling is a hot topic!
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 procedural modeling
 fence
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Looks like a good start. Keep pushing it further, use more layers, vary everything. Vary the pscale by the age or distance, make volumes from the particles and sim those. There's no "make beautiful" button just keep at it.

You can make a simple twist deformer, rotate around origin and vary the twist by distance from the origin. Then animate the twist and the spin, calculate the velocity with a trail sop, use it as a source for a volume. https://academo.org/demos/rotationaboutpoint/ Tighe

Put the primitive shape outside of the shoe shape. Put point normals on the shoe. Pipe shoe into first input on wrangle, pipe primitive into second input. Use intersect function to ray the shoe to the primitive along normal, animate the activation. That should give you the effect. Build more controls as necessary to get the look/timing you want. T

haha that means the sharing is working Happy to hear that you find the gradient and curl direction useful, mind if I ask what uses you've thought of for it? I developed this method when making grass patches and found that using it in tandem with curvature it lets you groom pretty easily, well at least give you a good starting point. The differential growth that can be made with the curvature is kind of a plus. Interested to hear all the different uses people can think of. Tighe

Check out the two recent masterclasses on FLIP by Jeff Wagner, he describes some awesome methods on air field implementation to get the effect of water falling through air by changing the density attribute of the FLIP volumes.

As I started reading the second paragraph in your response I too came to the conclusion of using a ray to get the lines to conform to the shape  haha. I don't ever use the ray sop, I use the intersect function in vex in a wrangle to project points when I need to, this way I can set the ray direction better and have finer control. Also using a higher resolution mesh to project to would give you a smoother result. A more intricate way of doing the ray that would account for a line that's already been projected above it(overlap). The method would be to iterate over each strand and project it to the geo, looking to see if there is another point within a cone of the points normal and an angle. Then you would only be able to ray by the distance of the two points multiplied by a parameter say .9. Hope this helps! Tighe

Create an id attrib on points, trail the points, run a for each over each id and you can get a u attrib by @density = chramp("fade",fit(@ptnum,0,npoints(0),0,1));, then create a fluid source and create a density volume by stamping points. You could also use just points and stamp the points and then use the motion blur tab in the fluid source but the first method I mentioned gives you more control. Hope this helps, Tighe

Yes, with the ROP alembic output node in sops. Should work in indie unless they changed the export permissions in H16. Tighe

Are you starting with a grid to get the bumpy form? If you are you could set it to rows, so you have line primitives with many points, process it to give it bumps and then for each row create as many duplicate threads as you want. Add noise to each of these threads an offset it slightly from the parent thread, this would essentially be a hair upres. Let me know if this makes sense, hope this helps. Tighe

Created a tool to calculate the gradient and curl along the curvature of a given geometry. If I'm understanding what you're looking for correctly I think this might help: (link to the file is in the vimeo description) It runs on geometry but there's no reason you can't go to and from volumes. Hope this helps, Tighe

Yea, group each object separately, merge them, file cache, and then when you read it you can then blast by group

Primitive sop can definitely help here. If using the copy/transform points method is the way you want to go, forgot to mention it but to calculate the centroid you'd do: vector min, max; bbox(0,min,max); addpoint(0,set(lerp(min,max,.5))); there's your centroid point. hope this helps. Tighe
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 copy stamp
 fragments

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https://www.sidefx.com/forum/topic/27585/ At the end of that sideFX thread it describes how to access the prim intrinsic information. You could also calculate a centroid point, then make your orientation transform, pscale and animation, which you would then then transform geometry to.
 13 replies

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 copy stamp
 fragments

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Posted a thread on some tools, one of which is how to calculate the concave curvature of a mesh. I've used it to get some pretty cool differential growth results. It runs on points only so it's pretty fast. Here's a link to the thread. Tighe

Hey everyone! Here's a demo of some point cloud tools I created to calculate concave and convex curvature as well as gradient and curl direction, also sharpening. Forgot to mention in the demo that the curvature calculation is a great way to do differential growth by advection along normal * curve * noise * parm. Also, the curl calculation can be used to make grass patches and groom fur by orienting curves along the direction to add swirly variance. There's a lot of ways these tools can be handy, interested to see what you all come up with! Let me know if you have any questions, enjoy! curveGradientCurlSharpen_v002.hipnc

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 point cloud
 sharpening

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Ah, thank you. I'll look in to this as a solve.