// undine docs
Quick Start
Five minutes from empty scene to a cached fluid mesh. No scene presets, no prior project: just Blender open.
The order of operations doesn't change between shots: tag objects → run the solve → review playback → mesh. The values change, the sequence stays.
1 · Tag the scene
Open the Undine panel and switch to the Objects tab. You're not creating new geometry here — you're assigning an Undine role to objects that already exist in the scene.
Pick the cube or volume that defines where the fluid can live and tag it as Domain. Pick each liquid source and tag it as Emitter. Pick the solid obstacles and tag them as Collider.
The Tagged in Scene counter confirms what's assigned at a glance. If it reads 0 domains, the solver won't start.
Minimum viable setup
- 1× Domain — defines the simulation bounding box
- 1× Emitter — the object that releases fluid
- 0–N× Collider — optional, anything the fluid should hit and slide around
- Clear Tags only when you want to strip every role from the current selection
2 · Run the solver
Switch to the Actions tab. Set Start Frame and End Frame, pick a simulation mode (PIC to start — it's the most stable), and toggle SNAP preset if you want to see the fluid move in the viewport while it solves.
If you have animated colliders, run Bake colliders (animated) first. It's a single click and prevents the SDF from drifting out of sync during the solve.
Run kicks off the sim. The panel reports live particle count, simulation FPS, and SNAP playback FPS. Stop pauses it cleanly.
Actions panel states
- Run — starts the simulation across the configured range
- PLAYBACK — appears once cached frames are ready for review
- Clear — wipes the current playback cache
- MESHIFY SIMULATION — turns cached frames into a mesh
- STOP MESHIFY NOW — interrupts an in-flight mesh build
- Store / Discard — keep or reject the generated mesh
3 · Review before meshing
When the solve finishes, scrub the range with PLAYBACK. If something's off (weird timing, fluid clipping a collider, chaotic dispersion), it's not worth meshing yet.
The Debug panel shows CFL, Poisson residual, and divergence per frame. A sustained CFL > 1.0 means dt is too large; a residual that doesn't drop means the Poisson isn't converging.
If everything looks right, move on to step 4. If not, head back to Sim Params, adjust, and relaunch. Fast iteration is the whole point of Undine.
4 · Mesh
Meshify tab (or hit MESHIFY SIMULATION from Actions). First step: pick a mesh preset. That fills in voxel size, influence radius, smoothing, Taubin, anisotropy, and backend.
Use Preview or Draft while iterating. Once the look lands, switch to Final Ultra and let the final mesh build run while you grab a coffee.
Store keeps the result in the mesh cache. Discard drops it if it didn't pan out.
Next steps
Once the first solve works, the most useful next pages are object tagging, simulation parameters, fluid behavior, and mesh output — in that order.