Choosing an alignment approach¶
Moonshine offers three ways to make a projected image land where you want it, and picking the right one first saves a lot of undoing later.
The mental model¶
Every alignment problem is one of two problems, and they are fixed in different places.
The projector is in the wrong place, so its image is the wrong shape. The projector is off-axis, or tilted, or throwing onto a slightly curved wall. The image itself is correct — the geometry of the light is not. You fix this by reshaping that one projector's output, on the Warp tab.
The image is the right shape but the model is not. Your surface model does not quite match the real object in the room — the physical thing has a bulge, the truss sagged, the built set is 40 mm off the drawing. You fix this by moving the surface itself, in Warp mode on the Scene tab, and every projector lighting that surface picks up the change.
Which one to use¶
| Approach | Where you work | What it moves | Applies to |
|---|---|---|---|
| 4-corner keystone | Warp tab → 4-Corner | The four corners of one projector's output | That projector only |
| Bezier mesh | Warp tab → Bezier Mesh | A grid of control points across one projector's output, with curve handles | That projector only |
| 3D surface warping | Scene tab → Warp mode | Points on the surface model itself, in 3D | Every projector lighting that surface |
Reach for each one when:
- 4-corner keystone — the projector is off-axis and the image is trapezoidal on a flat surface. Four handles, one move each, done. This is the first thing to try on any flat wall or screen.
- Bezier mesh — the corners are right but the middle is not: a curved wall, a cyclorama, a soft-edge overlap that needs local correction, or lens distortion the corners cannot reach. You control how many rows and columns you get, and each point carries curve handles so a bend stays smooth instead of creasing.
- 3D surface warping — you are mapping an object, not a screen, and the model does not match the build. Pulling the model onto the real object fixes every projector at once and keeps them agreeing with each other, which four corners per projector never will.
On a flat screen, stop at 4-corner
A bezier grid can do everything four corners can, but every extra control point is another thing to knock out of alignment. Add rows and columns only where the surface actually needs them.
How the three relate¶
4-Corner and Bezier Mesh are two views of the same per-projector warp. They are not stacked layers. Switching from 4-Corner to Bezier Mesh for the first time builds a 2 × 2 grid from the corner positions you already set, so nothing is lost. Afterwards the two stay tied together: dragging a corner handle in 4-Corner carries the whole grid — interior points included — along with it, and dragging a grid corner in Bezier Mesh updates the four corners.
3D surface warping is separate, and it is shared. It changes the surface, not any one projector's output, so it survives changes to projector placement and is visible to every projector aimed at that surface. It is also the only one of the three that several operators can edit at the same time — see Editing a surface together.
A working order¶
- Place your surfaces and projectors in the Scene. Get the physical positions roughly honest before correcting anything — alignment work built on a badly placed projector has to be redone when you move it.
- Square up each projector on the Warp tab with 4-corner keystone.
- If the surface is curved or the middle still drifts, switch that projector to a bezier mesh and add rows and columns only where you need them.
- For object mapping, switch to the Scene tab and sculpt the surface in 3D until the model sits on the real object.
- Bake the warp so the show renders from the aligned surface rather than the source model.
Before you start¶
- Alignment is per projector for keystone and bezier work, so select the projector you mean to correct first. See Projectors.
- Working on a warp takes a lock, so two operators cannot fight over the same projector's corners. See Locks.
- Ctrl+Z undoes alignment work everywhere in this section, and Ctrl+Shift+Z redoes it. On the Warp tab, a run of quick arrow-key nudges collapses into one undo step; in 3D surface warping each nudge is its own step.