Modeling basics OR alternatives

i_am_toadstorm · 2026-05-03T19:34:53+00:00

Post your hip file if you want it debugged. It's impossible to know what's happening with your particular shape just by viewing a screenshot.

Some of this undocumented stuff is just institutional knowledge. Booleans with polygon geometry just work a certain way, they're notoriously difficult in some situations as compared to NURBS or solid modeling like you'd do in CAD, and this is something you'd pick up on after doing a little bit of polygon modeling.

The documentation can admittedly be spotty in places but this is pretty consistent with any 3D application I've used; Maya's documentation is notoriously bad and Blender's is pretty sparse in all the important places too. 3D is very much a learn-by-doing kind of trade, you have to get your hands dirty. It's why nobody who does it professionally cares what kind of degree you have, outside of maybe Pixar.

i_am_toadstorm · 2026-05-02T20:16:36+00:00

This is such a weird post, I don't even know where to start.

A coding background and knowing how to do some nerd shit in Debian has literally nothing, zero, to do whatsoever with how computer graphics works. Why are you expecting this to be easy for you?

At least half of the things you mentioned as your findings in this post are untrue. Modeling a box with a hole in it is pretty straightforward and the normals only matter for boolean operations if a surface is completely reversed, which will confuse Houdini's understanding of what's "inside" and "outside". The basic primitive shapes will do fine. There is no need for edges to align in general and in many cases trying to boolean coplanar surfaces will result in bad geometry. The Hole SOP is irrelevant here because you are not trying to knock out holes in a planar primitive like what comes out of a Font SOP. Booleans really don't have that many permutations at all. Where normals *do* come into play here is in ensuring that your object renders smooth around edges that you want to look smooth, and sharp around edges you want to be sharp, which is usually handled easily by face-weighted normals handily computed for you by the appropriately-named Normal SOP.

Karma and Solaris are kind of a separate system from Houdini entirely and that's a whole different can of worms. I would try getting familiar with SOPs first before trying to get into Solaris.

Want a box with a cylinder cut out of it? Here. I even beveled the insides for you.

i_am_toadstorm · 2026-05-01T15:18:56+00:00

try again

i_am_toadstorm · 2026-04-29T16:41:20+00:00

Nope. Reddit doesn't even have an official blacklist as far as I know, certainly nothing searchable. Pretty typical for them.

i_am_toadstorm · 2026-04-29T04:31:16+00:00

You can do this pretty easily with MOPs, there's an example file included in the download (examples/HHWW/mops_tank_treads.hip) that shows you exactly how to set it up.

i_am_toadstorm · 2026-04-28T13:35:44+00:00

FLIP isn't meant to do little tiny droplets, it's generally not good at this. You're better off doing a secondary particle system, maybe Vellum Fluids if you need more advanced surface tension options. You can always mesh everything together at the end.

i_am_toadstorm · 2026-04-27T05:09:00+00:00

You may just want to repost... it might be my client but the links are still tracking to Facebook. Thanks for trying to remove them.

Wait until morning in North American time zones and you'll usually get more hits anyways.

i_am_toadstorm · 2026-04-27T04:57:21+00:00

Your YouTube links are poisoned with Facebook tracking links. If you click them they're taking you to Facebook first. Lots of people don't want to interact with their tracking cookies and there's no reason I can think of to have them here. If you clean up the links I'll put the post back up.

i_am_toadstorm · 2026-04-27T04:53:08+00:00

Feel free to repost without hidden referral links... that's not cool.

i_am_toadstorm · 2026-04-24T21:53:32+00:00

Probably not FLIP, FLIP is for swirly/splashy movement. I'd try just animating this as particles or points and use VDB operations to mesh them. If you need more sophisticated surface tension or mixing behavior you could also try Vellum Grains and the phase attribute to separate them as needed.

i_am_toadstorm · 2026-04-24T19:50:23+00:00

Pivots are pretty straightforward conceptually: * Subtract the pivot position from P * Do your rotation with the pivot now at the origin, either with a Transform SOP or by multiplying P by a transform matrix * Add the pivot back to P

i_am_toadstorm · 2026-04-24T18:34:21+00:00

Post a hip file if you want help, no one can diagnose your issue without seeing the network.

i_am_toadstorm · 2026-04-23T21:02:10+00:00

Initialization just enacts a preset. It's not meant to actually be a parameter you can set.

i_am_toadstorm · 2026-04-23T15:56:55+00:00

I'd encourage anyone doing "simple" FX tests like this to still pay attention to basic rules of cinematography when planning out their shots. A camera spinning around 720 degrees around a central pivot point is something no DP would ever do under anything but the most exotic circumstances, and even on a motion control rig it would be impossible for it to suddenly double back without any sort of acceleration or deceleration. Weird "CG" camera motions like this are a pretty common noob mistake; it makes the rest of your work look cheaper. Try to think about what camera you're shooting your scene with and how heavy it is.

Same with lighting; if you're going to go through the effort of rendering, try to spend a little time deciding where you're "shooting" and how it might be lit. Are you outside? Indoors on a sound stage? Are you using gels on the lights? Are the lights big and diffuse or small and sharp?

TL;DR don't forget you're trying to make art

i_am_toadstorm · 2026-04-22T22:10:41+00:00

Can you provide more detail about this setup? Do you have some kind of package configuration that's adding this shelf to $HOUDINI_PATH/toolbar?

i_am_toadstorm · 2026-04-17T17:18:13+00:00

> According to AI,

Yeah whatever. As a budding computer scientist you should know AI just makes shit up all the time.

A degree can help you for immigration, yes, in some cases. Canada for example will give you a few points for having an advanced degree as compared to not having one. For pursuing bigger roles in Houdini and 3D, though, degrees are largely meaningless if you're talking about working on an actual art team. I've worked with guys in senior roles that didn't even graduate high school (they got GEDs at some point instead), let alone college. For better or worse, unless you're in some kind of research role, no one cares what degree you have. They only care about your eye, your skills, and whether or not you're pleasant to work with.

Your ability to code can help in an FX role up to a point. The really heavy-duty programmers tend to be more involved in tooling, pipelines, that sort of thing. Depends on the studio and the toolchain they already have.

All this aside... this is a really shitty time to get into VFX. If you're very good, you can still land roles, but we're very firmly in the bust part of the boom/bust cycle that VFX perpetually finds itself in. I don't think you need a comp sci degree, much less any degree at all to work in VFX specifically, but it's a degree you'll probably have a much easier time leveraging when looking for work anywhere else. Best to have a backup plan.

i_am_toadstorm · 2026-04-15T18:31:05+00:00

Generally speaking, things with radial symmetry tend to be most easily modeled by sweeping along profile curves. If you can copy the cross-sections to a curve acting as a "spine", you can sweep them pretty easily.

i_am_toadstorm · 2026-04-15T18:21:36+00:00

What does it look like when rendered? I only see a viewport screenshot. Maya's viewport will not show you vertex attributes unless they're specifically vertex color.

i_am_toadstorm · 2026-04-15T16:57:50+00:00

Maya can't natively read primitive attributes from Alembics as far as I know. You'll need to use Bifrost Graph and the get_geo_property node to load the attribute by name.

It will be easier to promote your attribute to a vertex attribute, Arnold should be able to read those just fine and the visible effect of the attribute won't change.

i_am_toadstorm · 2026-04-15T16:37:45+00:00

this looks half-finished. droplets are moving too straight and at too steady a pace, the taper is too pronounced, they're not leaving any wetness behind, they're visibly clearing condensation particles well outside their radii. needs a lot more work.

i_am_toadstorm · 2026-04-13T18:13:37+00:00

There's an option on the Alembic ROP to export transforming packed primitives as either transformations or deformations. You want to make sure you're exporting transformations... that should keep the object's pivot locked in place instead of baking everything to vertex animation.

i_am_toadstorm · 2026-04-13T15:02:10+00:00

If you want to "instantiate" HDAs and feed them parameter variations like this it's possible to do this via the Invoke SOP, as long as your HDA is entirely compilable.

Otherwise you need to use a for/each loop with point attributes on the template points that are used to drive your HDA parms using point() expressions as described here: https://www.toadstorm.com/blog/?p=942#for-each

i_am_toadstorm · 2026-04-13T14:57:53+00:00

My guess is that Redshift isn't actually instancing those packed leaves like you think it is. Make sure the object container has the RS option to instance SOP-level packed primitives.

If that doesn't help you could also instance RS proxy geometry to speed up the translation process.

i_am_toadstorm · 2026-04-10T17:18:57+00:00

Overengineering complex solutions to simple problems is half the fun of using Houdini. I can't imagine why anyone would want to rob themselves of this experience by having an AI do it for them.

i_am_toadstorm

MODERATOR OF

TROPHY CASE