# cubiccube

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1. ## Solaris camera

There are some good example hip files inside of the support materials for Solaris in the h18 docs that might answer some of your questions. The download link is buried in here: https://www.sidefx.com/docs/houdini/solaris/tutorials.html
2. ## Solaris camera

Do the materials keep their assignments? I'm able to bring materials into lops with the scene import lop but still have to manually reassign them to their respective groups.
3. ## BulletSOP 2.0.15

This just made my day. Thanks Milan!
4. ## Sand dripping simulation

Searching for "variable viscosity" on here should point you in the right direction. If you've got more questions just post a hip file of your setup.
5. ## reverse rigid dynamics effect

Stack a couple Voronoi split sops with a grid piped into input 2.
6. ## Procedural Burn WIP

This is my first real foray into working with the pyro solver. The setup is totally procedural..just have to specify where to start the burn. The geometry functions as a collision surface but also converts to fuel as it is burnt away. Now that I have the system all setup I'm going to focus on getting sharper, more dramatic flames (a la self-immolating monks), and a less crappy render for my next revision. If I had more time it'd be interesting to get the collision geometry to act as a rigid body when/if it ever it becomes separated from the main structure. That way any separated chunks would fall to the ground instead of just floating in space. This isn't that important to the overall effect, but it's an interesting problem that would be fun to solve. I'd love to hear if anyone has any ideas on how to approach something like this.
7. ## fill pointcloud positions "up-res" particles

A Point Replicate Procedural geometry shader w/proper CVEX logic could probably achieve this. You might find this recent thread helpful too: http://forums.odforce.net/topic/19359-is-there-a-way-to-create-uniform-evenly-sized-voronoi-pieces-in-h13/?hl=voronoi
8. ## Timer

Here's a simple setup for a timer inside a simulation context. I like using a "state" attribute where 0 = ready, 1 = active, and -1 = dead. This is handy for controlling things like debris emission too. simple_timer_v01.hipnc
9. ## point cloud import - point.number - in DOPs

In order to get your "neighbour" attribute to write properly, it needs to be created and fed into the while loop. Check out the attached file (go to frame 2). sopsolver_pointcloud_fix1.hipnc
10. ## BulletSOP 2.0.11

As always, thanks for all your great work!
11. ## Debris based on distance

The technique you're describing is a good way to determine when to start emitting debris (when two points or prims that started off as neighbors become pulled apart --> emit debris) but I'm not sure you want to use this kind of distance based logic to stop emissions. Consider two faces that stay within the distance threshold will continue emitting indefinitely. A timer might be more useful here, as it guarantees you'll stop emitting at some point. Regardless, you can do distance calculations pretty easily in VEX using point cloud lookups. Be sure to store initial neighbors as attributes first.
12. ## Dynamic duplication effect

There are a lot of ways you could go about offsetting the timing (duplicating your foreach sops and staggering the timing of their switches or something along those lines), but I'm not sure this is the best way to solve the "linear" look you're talking about. You'll get a more seamless effect if, instead of scattering points on top of the actual geometry, use the property point position (with a very small random offset, +/-.1) as the origin for your new piece points (you can use a line or add sop to make the initial points or, in H13, use Attrib Wrangle).That way everything originates from the same spot and explodes outward instead of appearing in midair. Not exactly the answer you're looking for but give it a shot and see if it helps. Also, you scene will simulate much more quickly if you bring the polygon count on your geometry way down. Pipe the initial geometry into a shrink sop to generate a convex hull (what Bullet converts your geometry into anyway) and play with the sliders until you get something closer to 100 polys. Good luck!
13. ## Is there a fast way to delete all points that occupy the same space?

I like VEX for this sort of thing, especially now that we can add/delete geometry with Attrib Wrangle. Here's an example file. delete_inside_faces_v01.hipnc
14. ## BulletSOP 2.0.10

Nice! Thanks for this!
15. ## Dynamic duplication effect

You can get that kind of jitter using basic sine functions. You could also use some noise. Or both: use sine functions to get your oscillations and use noise to vary the frequency and amplitude. You could do these with expressions if you wanted but imo a vopsop or wrangle node is more quick and clean. The other component to the jitter in your reference is that it builds as the boxes get closer to splitting. In my example file I was assigning a randomized counter to each box once its velocity dropped below a certain threshold. You could use that same counter (or another based on different logic) to drive the ramping up of the jitter. Now, implementing it with BulletSOP might be a little tricky since you can only animate static (mass = 0) objects. I believe there's an example in the hip file Milan includes with each release that shows how to get around this by stashing your objects mass and swapping it out when you want it to become active.
16. ## Dynamic duplication effect

What Houdini build are you using? And what BulletSOP version? BulletSOP should be v2.0.9 and Houdini 12.5.469 is recommended (though I'm on 12.5.536 without problems).
17. ## Dynamic duplication effect

This sounded like a fun problem and a perfect one to solve with Milan Suk's BulletSOP. Sorry if this doesn't directly answer your question about a DOPs based workflow, but I couldn't help myself You'll need the latest BulletSOP (v2.0.9) for the example file to work. You can grab it here: http://forums.odforc...-bulletsop-209/ btSop_dynamic_split_v01.hipnc
18. ## Is there a faster way to instance geometry onto particles?

Strange. No crash for me on 12.5.536. I changed it to start on frame 1 though, so give that a try.
19. ## Is there a faster way to instance geometry onto particles?

Yeah. As long as you have a stable correspondence (ie. ID or piece attrib) between sets of geometry, you can use a vopsop or wrangle to swap attributes between them. The Find Attribute by Value function is the easiest way to do this in vops but you can also do it with some point cloud trickery. Here's another example file to check out. I'm using a Copy SOP to stamp the initial pieces but everything else is handled by vex. The final transforms are handled by vex as well but, if you're using heavy geometry, instancing might be a better solution. vop_reveal_v01b.hipnc
20. ## Is there a faster way to instance geometry onto particles?

Yeah, the Copy SOP is painfully slow for this type of thing..use a vopsop instead. Also, you'll probably want to orient your pieces at some point. Just search around..there are a bunch of threads on here about doing that with vops. reveal_List_of_Stuff_02_fix.hipnc

23. ## how do you aproach this car-glass shatter?

Here's a quick example using voronoi fractures, like Wesley mentioned. glass_shatter_v01.hipnc
24. ## Houdini Performance

On the DOP network node there's a "reset simulation" button, plus other controls for caching.
25. ## save point position data across frames in sop solver

What are you using the old P values for? If it's for something like particle avoidance (making particle A avoid where particle B has been), you can leave a trail of points behind B in the sop solver and use vops + pc lookup to do the repulsion, then delete the trailed points outside of the solver. If this isn't what you're after, maybe tell us more about the effect you're trying to achieve.
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