jkunz07

Of course! I should have mentioned that the use of $HFS assumes you have the Houdini environment setup in the shell or have launched Houdini Terminal inside the Utilities folder of the app directory.

Those modules exist in $HFS/houdini/python2.7libs/ So if your on a mac you can do open -t $HFS/houdini/python2.7libs/objecttoolutils.py in the shell to check out what's going on with the customStateTool function.

I think most are written in Python but Hscript is supported as well. If you right-click on a shelf tool, then click "Edit Tool..." it will allow you to see how the code that the tool is calling. This code is found under the script tab.

Have you tried the Intersection Analysis SOP?

The variable for total number of points is @numpt. There is a function npoints() which is different for a variable. npoints(0) (the zero specifies the input geometry) will return the same result as @numpt. This part of the docs might be worth looking at: http://www.sidefx.com/docs/houdini/vex/snippets.html#indexing

@numelem is the total number of elements being processed. Depending on the what the wrangle is set to operate on (points, vertices, prims, or detail). You could use npoints() or nprimitives() vex functions instead if you want. The code is generating a random number between 0 and 1. This is then scaled to fit the number of points (multiplying by @numelem). floor() function eliminates anything after the decimal, so we have a whole number. Then we check if it matches the current element number (@elemnum). If it matches, this will evaluate to 1, adding it to the group, the rest of the points that don't match will evaluate to 0 and not be included in the group. Is that clear? Let me know if you have any more questions.

i@group_single_point = floor(rand(chf('seed'))*@numelem) == @elemnum; Something like this should work

You should be able to use the POP Axis Force node to apply vortex style force to Vellum sims, all the POP force nodes will work with Vellum http://www.sidefx.com/docs/houdini/nodes/dop/popaxisforce.html

http://ianwaters.co.uk/wp/mash/the-papers-behind-the-world-node/ http://algorithmicbotany.org/papers/ecosys.sig98.pdf https://disney-animation.s3.amazonaws.com/uploads/production/publication_asset/135/asset/vegetation2016_v9.pdf https://dl.acm.org/ft_gateway.cfm?id=2947692&type=pdf&path=%2F2950000%2F2947692%2Fsupp%2Fp57-cieri-supp.pdf&supp=1&dwn=1

Have you made sure the boolean SOP is set output 'binsidea' group, and that that group is specified in the final normal SOP?

'unique points along seams' shouldn't be necessary. Try this file where I've added normals to the geo before it's cut, also having normals on the cutting geo can help. Finally only the inside faces get normals recalculated after it's shattered using the A inside B group. This preserves the smooth normals of the sphere's shell before it's shattered. BooleanSeamless.hipnc

We can also use the fbres file to control the dropdown list of presets. FBres file (for customizing the list of preset resolutions in pop-up menus on render nodes, lights, and cameras). http://www.sidefx.com/docs/houdini/basics/config.html#configuration-files

You can use the uv texture SOP to project uv's from your camera. The Z component of the uv will be the particle's distance from your camera. You can then use that in an attribute create SOP, wrangle, etc. when creating pscale so that the particles are larger when further from the camera. You can also use these uvs to group or delete particles which are too close or far from your camera or outside the frustum. pscale_from_camera_distance.v1.hipnc

each voxel contains the height of the terrain at that grid point http://www.sidefx.com/docs/houdini/model/heightfields

http://www.vam.ac.uk/content/articles/a/computer-art-history/