Bezier mesh¶
Bend a projector's output through a grid of control points when four corners cannot follow the surface.
Use this for curved walls, cycloramas, sagging screens, soft-edge overlaps and lens distortion — anywhere the corners are right but the middle is not. Like 4-corner keystone, it works on one projector at a time.
Open the editor¶
- Open the Warp tab and choose a projector.
- Set the sidebar's mode switch to Bezier Mesh.
The first time you switch, Moonshine builds a 2 × 2 grid from the corner positions you already set in 4-Corner, so no alignment work is lost. Switching back and forth after that is free — the two modes share the same four corner positions.
What you are looking at¶
| On the canvas | What it means |
|---|---|
| Dashed rectangle | The projector's uncorrected output frame |
| Fine wireframe | The bent surface the projector will actually output |
| Heavier lines | Grid lines — the rows and columns connecting your control points |
| White squares | Control points |
| Orange squares | The four corner points, shared with 4-Corner mode |
| Red and green dots | Curve handles on the selected point (red for left/right, green for up/down) |
The selected point fills indigo and grows slightly, so you can always tell which one the sidebar and the arrow keys are pointing at.
The wireframe is drawn at a fixed density that does not change when you add or remove rows and columns, so it always reads as the shape of the surface rather than the count of your control points.
Set the grid size¶
Grid Size in the sidebar has a Rows and a Cols stepper, each with a − and a +. The grid runs from 2 × 2 up to 50 × 50.
Pressing + places the new points on the current surface, so the shape you have already built does not jump when the grid gets denser.
Pressing − is coarser: it re-spaces the whole grid evenly and rebuilds it to approximate the shape you had, so points you positioned by hand will shift. To drop one line and leave every other point exactly where it is, delete it on the canvas instead — see Insert and delete lines.
Add points where the error is
A uniform 10 × 10 grid is usually the wrong answer. Start at 2 × 2 or 3 × 3, find where the image still misses the surface, and insert a line right there (see below). Fewer points means fewer things to bump.
Move a point¶
- Click a control point to select it. The sidebar's Selected Point panel shows its grid position as
R# C#, its index, and its X and Y coordinates to four decimals. - Drag it, or nudge it with the arrow keys.
The coordinate figures are a read-out — move the point by dragging or nudging it rather than typing a value.
Corner points also drive the 4-Corner view: move one here and the projector's keystone corners follow.
Move a whole row or column¶
Hover a grid line, away from any control point. The cursor changes to a resize cursor and the line highlights. Drag it to move every point on that line at once — the fastest way to correct a whole band of the image without touching its shape.
The drag is constrained to one axis: a row line (horizontal) moves up and down, a column line (vertical) moves left and right.
Insert and delete lines¶
| Input | Result |
|---|---|
| Ctrl (or Cmd) + click a grid line | Insert a line across the one you clicked, exactly at the pointer |
| Alt + click a grid line | Delete the line you clicked |
| Right-click a grid line | Menu: Add Column Here / Add Row Here, plus Delete Row n or Delete Column n |
| Right-click a control point | Menu: Delete Row n, Delete Column n, and Collapse Handles or Expand Handles |
While Ctrl is held the preview line turns green and shows exactly where the new line will land; while Alt is held the line you are about to remove turns red. The cursor picks up a matching plus or minus badge, so you can tell insert from delete before you commit.
Clicking a horizontal line with Ctrl inserts a column at that point, because the new line runs across the one you are pointing at. Clicking a vertical line inserts a row.
Deleting is refused below 2 rows or 2 columns. When a line is removed, the surviving points keep their exact positions — only the lines either side of the gap have their facing handles rescaled to span the wider cell.
Curve handles¶
Handles are what stop a bend from creasing. They appear on the selected point only: four dots joined to the point by dashed leaders, red for the left/right pair and green for the up/down pair.
- Drag a handle dot to change how the surface leaves that point in that direction. The sidebar shows the selected handle's name and its dX / dY offset.
- Double-click a handle dot to collapse it back to zero.
- Double-click a point whose handles are collapsed to expand them again, each reaching a third of the way to its neighbor.
- Or use Collapse Handles / Expand Handles from the point's right-click menu.
Linked and independent¶
The Handles switch on the selected point has two settings, and H toggles between them:
| Setting | Behavior | Use it for |
|---|---|---|
| Linked | Opposite handles mirror each other — move the right one and the left one follows | A smooth, continuous curve through the point |
| Independent | All four handles move separately | A deliberate crease or a corner in the surface |
Switching back to Linked snaps the left handle to mirror the right, and the up handle to mirror the down, so the point becomes smooth again immediately.
The points of a freshly built grid start linked. Points that appear later — one you insert with Ctrl + click or from the right-click menu, or one whose collapsed handles you expand — start independent, so set them back to Linked if you want the curve to stay smooth through them.
Keyboard¶
| Key | Action |
|---|---|
| Up Down Left Right | Nudge the selected point, or the selected handle if one is selected |
| Tab | Cycle to the next control point |
| Shift+Tab | Cycle to the previous control point |
| H | Toggle the selected point between linked and independent handles |
| Esc | Deselect |
| Ctrl+Z / Ctrl+Shift+Z | Undo / redo |
Arrow Key Sensitivity in the sidebar sets the nudge distance, from 1 to 100, starting at 50. Turn it down for the final pass and up while a point still has a long way to travel. A rapid run of arrow presses collapses into one undo step.
The arrows drive the selected handle when one is selected, and the point itself otherwise — click the point again, or press Esc and reselect it, to get back to moving the point.
Click inside the editor canvas once before using the keyboard; the shortcuts follow the canvas, not the sidebar.
Zoom and pan¶
| Input | Action |
|---|---|
| Scroll wheel | Zoom, centered on the pointer (25% to 400%) |
| Middle-button drag | Pan |
| Double-click empty canvas | Reset zoom and pan |
The zoom percentage sits in the bottom-right corner, with a Reset button beside it whenever you are not at 100%.
Reset the mesh¶
Reset Mesh asks for confirmation — Reset Mesh?, with Cancel and Reset — then lays every control point back out on an even grid, handles expanded and linked. Your row and column counts are kept, and so is the four-corner shape: the grid is rebuilt inside the corners you set in 4-Corner mode rather than snapping back to a rectangle.
To clear the corners as well, switch to 4-Corner and use Reset All Corners.
Working with other operators¶
A projector's keystone and bezier work share one lock. If someone else has it, the controls are disabled until they finish. See Locks.