Working well

Troubleshooting

Almost everything that goes wrong is one of about fifteen things. Rhea's panel warnings name most of them directly; this page covers the rest and explains the causes.

Nothing happens when I press the button

The button is greyed out: A required input is missing. The panel says which — usually no component assigned, or no base set. Rhea disables rather than failing on press, so a grey button is always a missing precondition and never a bug.
The wrong object was active: Every module acts on the active object. If you added the component last, it is the one selected. Click the base first.
The result is inside the base: Thickness or height at or near zero puts every copy flush with the surface. Raise it and see whether something appears.
It ran and produced nothing visible: Check the result line under the button. If it reports zero faces, the operation genuinely produced nothing and the cause is upstream — usually a field with no variation, or coverage at zero.

The warning will not go away

Panel warnings persist deliberately — self.report() messages vanish and are useless. But a persistent warning is sometimes just stale.

The classic: I generated a field but the warning remains

The field landed on a different object. Fields write to the active object, and if the component was selected when you pressed generate, that is where it went. The warning offers a Write to base button precisely for this — it is the fastest fix.

Tessellation problems

Copies are stretched or squashed: Non-uniform object scale, on the base or the component. Ctrl+A → All Transforms on both. This is the single most common cause of a result that is subtly wrong with no obvious explanation.
Copies point the wrong way: Inconsistent face normals on the base. Recalculate them, or use Rotate faces if the winding rather than the normal is the problem. Turn on the face orientation overlay to see which.
Copies are inconsistently rotated: Face winding varies across the mesh. Rotate faces is the tool that exists for exactly this. If they are consistently wrong rather than inconsistently, use the Step offset control instead.
Seams are not welding: The component's boundary vertices are not on the cell edges, so they never meet their neighbours. Also check that Scale is at exactly 1 — below it, copies sit apart by design and cannot weld.
Twice as many copies as expected: The base is triangulated. Run Triangles to quads first, or set the ngon mode appropriately.
It refused with a budget message: Base faces × component vertices exceeded the budget. Simplify the component, lower the density, or raise the budget in preferences — read the number in the message first. See Performance.

Everything looks like a soft blob

In Blender 4.1 and later, a face is smooth unless an edge is marked sharp, and a freshly generated mesh has no sharp-edge data at all. So every hard corner renders rounded and every result looks like the same soft lump.

Turn on the module's angle-based Shade smooth option. It computes fold angles and marks the sharp edges, so hard edges stay hard. This is the fix for “every Conway operator looks identical” and for a large share of “my result looks wrong” generally.

Conway problems

It refuses, saying non-manifold: Conway operators are only defined on closed manifold surfaces. Turn on the boundary edge overlay to find the holes.
Every chain looks the same: Three causes, usually all at once: shading is fully smooth so edges are invisible, canonicalize is off so the forms are lumpy, and kis height is near zero so that operator is doing almost nothing.
The result is lumpy, not regular: Turn on canonicalize. Raw Conway output is topologically correct and visually irregular; canonicalisation is what makes it look like the solid you expected.
It refuses on face count: Chains grow geometrically. Use a smaller seed — a tetrahedron rather than a dodecahedron — or a shorter chain.

Field problems

The field is flat, all one value: Either the generator found no variation — curvature on a perfect plane really is constant — or the modifier chain flattened it. Turn on the heatmap overlay and disable modifiers one at a time.
Contrast destroyed the variation: Check normalise is on. Contrast operates over the field's own range, but an un-normalised field that spans an unexpected range can still end up compressed to nothing.
The field is speckled: Computed fields are noisy at the vertex level. Two or three blur passes keep the structure and remove the speckle.
The formula shows a red error: The message names the character position. Most common causes: a function not in the allowed list, a variable name that does not exist on this mesh, or an unbalanced bracket.
Nothing responds to my field: Check the attribute name matches exactly — the consumer looks it up by name and a typo silently gives no variation. Check Variation is not zero.

Solver problems

Growth tears itself apart: Lower the step size. The integration is explicit Euler and it is only stable while each node moves a small fraction of the way to its neighbours.
Growth does not grow: Raise the growth rate. Without it, growth depends entirely on repulsion stretching segments past the split length, which it can only manage by tangling the curve.
Reaction-diffusion looks like static: It has diverged. Lower the time step. Divergence is clipped for display, so it appears as a fine checkerboard rather than an obvious error.
Reaction-diffusion produces nothing: Either it has not run long enough — patterns need a thousand iterations or so — or the feed and kill rates have fallen off the narrow band where anything happens. Go back to a preset.
The form-finding solve collapses: Nothing is pinned. Turn on pin boundary, or set a pin group. An unconstrained solve converges to a point.
The solve oscillates: Relaxation is too high, or two constraints are fighting. Lower relaxation first; rebalance weights second.

Installation and startup

The Rhea tab is not there: Press N in the 3D viewport to open the sidebar, and check the add-on is enabled in preferences. On Blender 4.0 and 4.1, legacy add-ons install disabled.
Errors after updating: Restart Blender. Python modules stay loaded for the session, and a half-reloaded package produces errors that vanish on restart.
Two of everything: Both the extension and legacy zips are installed. Remove one.
It refuses to write to a mesh: The mesh is linked or library-overridden. Rhea will not write to those, and says so rather than failing quietly. Make it local first.

Reporting something

If you hit something not covered here, the useful report includes:

Blender version and which of the two zips you installed.
Which module and what you pressed.
The exact text of the panel warning or the console traceback.
The result line, if there was one.
A screenshot — it usually says more than the description.

Support is at Superhive, and the Help & support section at the bottom of the panel links there directly along with the version number you will be asked for.