{"id":213697,"date":"2025-11-17T07:00:00","date_gmt":"2025-11-17T06:00:00","guid":{"rendered":"https:\/\/digitalproduction.com\/?p=213697"},"modified":"2025-11-13T10:09:17","modified_gmt":"2025-11-13T09:09:17","slug":"houdini-21-like-good-wine-part1-vfx-geo","status":"publish","type":"post","link":"https:\/\/digitalproduction.com\/2025\/11\/17\/houdini-21-like-good-wine-part1-vfx-geo\/","title":{"rendered":"Houdini 21: Like good wine (Part1, VFX & Geo)"},"content":{"rendered":"\n

A tasting of the dynamics and geometrys side (of) effects<\/strong><\/h3>\n\n\n\n

This release is not about the number of features, but about finishing what was started, achieving true production readiness, robustness, performance, and ease of use. It\u2019s a version focused on quality of life. Feature sets like MPM simulations and Karma have matured like a good wine. The machine learning tools respect the artist\u2019s skill set and have left their state of play are actual usefull in production.<\/p>\n\n\n\n

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SideFX’s R&D priorities presented at Equinox Hive Keynote<\/figcaption><\/figure>\n\n\n\n

Even though SideFX remains modest in its official statements, Houdini 21 is a massive release. For the feature-hungry among us, the highlights include a fully matured APEX; a refined and clever animation and rigging framework; a simulating Copernicus (think Substance on Dope<\/em>), and in the VFX realm, the production-ready MPM Solver. On top of that, we\u2019re seeing machine learning tools popping up in all the right places (AI for people who don\u2019t expect a Pixar film from a single click), faster and expanded rendering with Karma, and a healthy dose of quality-of-life improvements.<\/p>\n\n\n\n

Since our editorial cat can only count to 300, we can\u2019t tell you the exact number of new or improved features, but we\u2019re impressed nonetheless. And soon, you will be too. To avoid overwhelming both writer and reader, we\u2019re breaking this article into a mini-series. We\u2019ll start with VFX & Geometry, followed by Solaris & Karma, Copernicus & Terrain, and the massive Animation & Rigging tools.<\/p>\n\n\n\n

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The beaut of MPM. Art by Peter Sanitra<\/figcaption><\/figure>\n\n\n\n

MPM<\/h3>\n\n\n\n

One of the most exciting additions in H20.5 was without question the MPM Solver. The M<\/strong>aterialP<\/strong>ointM<\/strong>ethod truly allows you to simulate a wide range of different materials. From water, snow, and sand to honey, metal, and concrete, all within a single Solver setup. The geometry is simply substituted by points or particles, which are then simulated. The different materials interact physically accurate and constraint-free, purely based on their assigned parameters.<\/p>\n\n\n\n

The initial release was already impressive, but it left users standing somewhat in the simulated rain when asking: \u201cHow do I get a proper mesh with UVs?\u201d<\/em> That exact issue has now been beautifully solved in H21. Any MPM simulation, whether rigid body or fluid, can now be meshed (as polygons or SDF volumes), including UVs, color, and other attributes, using no more than two nodes. <\/p>\n\n\n\n

A nice and usefull addition to this workflow is the MPM Debris node, which generates new points along fracture lines as sources for smoke, dirt, or secondary debris effects. So let\u2019s take a look at meshing hard and fluid or granular surfaces across a few setups and scenarios and wrap things up with a creamed cookies drink while watching the official and very excellent MPM demo.<\/p>\n\n\n\n

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MPM Configure comes with everything you need for a happy little MPM simulation.<\/figcaption><\/figure>\n\n\n\n
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Replacing the default collider and source with our own models<\/figcaption><\/figure>\n<\/figure>\n\n\n\n

Surfacing MPM Simulations<\/h3>\n\n\n\n

Testing time! For this test setup, we\u2019ll have a clay ball smash into a vase model, paying close attention to UV transfer and the generation of smaller fragments through the Debris Source. The easiest way to start an MPM simulation is by typing \u201cMPM Configure\u201d into the node search. This gives you a complete set of starter nodes right away. (Under MPM Configure<\/em>, you\u2019ll also find plenty of additional example setups for study or creative repurposing.) By the way, the MPM container on the far right controls the overall resolution of the entire simulation.<\/p>\n\n\n\n

We replace the default sphere with our own model and can now assign materials directly inside the mpmSource node and tweak them to our liking. It\u2019s genuinely fun. Feels a bit like a mini-game. Since a concrete material would be more realistic but also quite boring as a vase material, we went with Chunky Snow instead. The environment comes in via an Object Merge directly into the mpmCollider Sop, ready to go. Our clay ball, the antagonist of this little simulation, isn\u2019t a collider per definition but another mpmSource ready to be smashed, merged with the vase and given its own material behavior, Chunk Soil.<\/p>\n\n\n\n

To make sure the particles can actually see and \u201clove\u201d each other, we need to enable Particle-Level Collision in the solver. The new Auto Sleep feature helps keep the vase passive until the collision happens, preventing it from collapsing at frame one and saving quite a bit of compute time.<\/p>\n\n\n\n

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Let there be … snow?<\/figcaption><\/figure>\n\n\n\n
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What awounderfull mess … and soon mesh.<\/figcaption><\/figure>\n\n\n\n
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To get proper collisions, make sure to enable particle-level collisions.<\/figcaption><\/figure>\n<\/figure>\n\n\n\n

Since the clay ball will be meshed as a fluid and granular surface and the vase as a rigid object, we first separate the MPM particles using a Blast node, filtering them by their respective source names.<\/p>\n\n\n\n

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