Bezier mesh

Bend a projector's output through a grid of control points when four corners can't follow the surface.

Use it for curved walls, cycloramas, sagging screens, overlaps and lens distortion: anywhere the corners are right but the middle isn't. Like 4-corner keystone, it works on one projector at a time.

Open the editor

1. Open the Warp tab and choose a projector.
2. Set the sidebar's mode switch to Bezier Mesh.

The first time you switch, Moonshine builds a 4 × 4 grid from the corners you set in 4-Corner, so your alignment carries over. After that you can switch back and forth freely, because the two modes edit one warp. Moving a corner in 4-Corner carries the whole grid with it, and the bends you make here show in the 4-Corner view and in the output.

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 output
Brighter lines	Grid lines: the rows and columns that connect 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 (a corner point stays orange) and gets slightly larger, so you can see which point the sidebar and arrow keys are acting on.

The wireframe is drawn at a fixed density, however many rows and columns you use, so it shows the shape of the surface rather than your grid.

Three buttons in the toolbar, after the projector's name and before the zoom buttons, choose what's drawn under the points:

• Video shows what the projector is playing, seen from its lens and bent through the mesh as you drag. This is what the projector will throw, before its mask and blend. It starts off, because drawing it adds rendering work.
• Grid shows or hides the wireframe and grid lines. The points and handles stay visible.
• Fill tints the bent surface.

The arrow beside Video sets how strongly the picture shows, so the lines stay visible over it. It starts at 25%. The Warp tab keeps its own setting, separate from the Mask tab and the Outputs canvas.

Set the grid size

Grid Size in the sidebar has Rows and Cols steppers, each with − and + buttons. The grid can be anywhere from 2 × 2 to 50 × 50.

+ places the new points on the current surface, so the shape you've built doesn't move when the grid gets denser.

− spaces the whole grid evenly again and rebuilds it to approximate the shape you had. Points you placed by hand will shift, and every point's handles become linked again. To remove one line and leave every other point where it is, delete that line on the canvas instead. See Insert and delete lines.

Add points where the error is

A uniform 10 × 10 grid is rarely the answer. Start at 2 × 2 or 3 × 3, find where the image still misses the surface, and insert a line there (see below). Fewer points means fewer things to bump.

Move a point

1. 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 decimal places.
2. Drag it, or nudge it with the arrow keys.

The coordinates are for reading only. Move the point by dragging or nudging it.

Moving a corner point here also moves the projector's corners in the 4-Corner view.

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 to move every point on that line at once. This is the quickest way to shift a whole band of the image without changing its shape.

The drag is locked to one axis: a row (a horizontal line) moves up and down, and a column (a vertical line) moves left and right.

On a phone or tablet, press on the line and drag. Points, handles and lines respond to a finger from a little further away than to a mouse.

Insert and delete lines

Input	Result
Ctrl (or Cmd) + click a grid line	Insert a line across the one you clicked, 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 you hold Ctrl, a green preview line shows where the new line will go. While you hold Alt, the line you're about to delete turns red. The cursor also shows a plus or minus badge, so you can tell which you're about to do.

Because the new line runs across the one you click, Ctrl + clicking a horizontal line inserts a column, and clicking a vertical line inserts a row.

You can't delete below 2 rows or 2 columns. When you delete a line, the remaining points stay exactly where they are. Only the handles facing the gap are rescaled to span the wider cell.

You can also delete an outer row or column. That edge of the image moves in to the next line. The 4-Corner corners don't follow, so the two views disagree until your next corner drag.

Curve handles

Handles keep a bend smooth instead of creased. They appear only on the selected point: four dots joined to it by dashed lines, red for the left/right pair and green for the up/down pair.

• Drag a handle to change how the surface leaves the point in that direction. The sidebar shows the handle's name and its dX / dY offset.
• Double-click a handle, or press H, to switch the point between linked handles (moving one moves its opposite too) and independent ones.
• Double-click a point whose handles are collapsed to expand them. Each one reaches a third of the way to its neighbor.
• Collapse Handles and Expand Handles are on the point's right-click menu.

Linked and independent

The Handles switch for the selected point has two settings. 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 curve through the point
Independent	All four handles move separately	A crease or a corner in the surface

When you switch back to Linked, the point is smooth again right away: the opposite handle snaps to mirror the one you double-clicked. On the outer edge of the grid, the handle pointing into the picture stays put and the one pointing outward follows.

Points in a newly built grid start linked. Points added later start independent: points from +, points you insert with Ctrl + click or the right-click menu, and points whose collapsed handles you expand. Set them to Linked to keep the curve smooth through them.

Keyboard

Key	Action
Up Down Left Right	Nudge the selected point, or the selected handle if there is one
Tab	Select the next control point. After the last one, it deselects and focus moves on to the next control
Shift+Tab	Select the previous control point. Before the first one, it deselects and focus moves back
H	Switch the selected point between linked and independent handles
Esc	Deselect
Ctrl+Z	Undo a point, handle or line move

Arrow Key Sensitivity in the sidebar sets the nudge distance, from 1 to 100. It starts at 50. Turn it down for the final pass and up when a point has a long way to go. A quick run of arrow presses is one undo step.

Undo covers moves, not changes to the grid

These can't be undone: adding or deleting rows, columns and lines, collapsing or expanding handles, switching Linked / Independent, and Reset Mesh. In this editor, Ctrl+Shift+Z doesn't redo a move you undid, so redo it by hand.

When a handle is selected, the arrow keys move the handle. Otherwise they move the point. To go back to moving the point, click it again, or press Esc and select it again.

Click the editor canvas once before using the keyboard. The shortcuts work only while the canvas has focus.

Zoom and pan

Input	Action
Scroll wheel	Zoom, centered on the pointer (25% to 400%)
Drag on empty canvas	Pan
Right-button drag away from the points and grid lines	Pan, as on the Mask tab. A right-click on a point or line still opens its menu
Middle-button drag	Zoom in (drag right or down) or out, around the point you pressed
Double-click empty canvas	Reset zoom and pan
Buttons at the end of the toolbar	Zoom out, zoom in, and Fit back to 100% with no pan

The zoom level shows in the bottom-right corner. On a phone or tablet, use the buttons to zoom.

Reset the mesh

Reset Mesh asks first (Reset Mesh?, with Cancel and Reset), then spaces every control point evenly again, with handles expanded and linked. You can't undo it. 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.

To reset the corners as well, switch to 4-Corner and use Reset All Corners.

Working with other operators

Keystone and bezier edits share one lock per surface, held by whoever has the Warp tab open on it. While someone else holds it, the controls are disabled for every projector on that surface until they leave the tab. See Locks.