Select, move and align
Short answer: Pick the Select tool (V) and drag a box, or press Ctrl+A to select everything. Drag the selection to move it. Hold Ctrl and drag to copy it. Use the arrow keys to nudge it. Select two or more molecules to get the align and distribute buttons in the top bar.
- Click Select in the left rail, or press V.
- Drag a box on empty canvas around the parts you want. Hold Shift while you drag to add to the current selection.
- Drag the selection to a new place. Hold Ctrl while you drag to drop a copy instead.
- Drag the round handle above the box to rotate. Drag a corner to resize.
- With two or more molecules selected, click an align button in the top bar.
Ways to select#
| Method | What it selects |
|---|---|
| Select tool (V) | Click an atom or bond. Drag on empty canvas for a box. |
| Lasso tool (L) | Draw a free outline around the parts you want. |
| Fragment tool | Click one atom or bond to get the whole connected molecule. |
| Ctrl + click | The whole molecule under the pointer, with any select tool. |
| Shift + click | Adds or removes one atom, bond, text box or arrow. |
| Ctrl+A | Every object on the canvas: structures, arrows, text, shapes, images and orbitals. |
| Double click an atom | Opens the label editor so you can rename it. |
Lasso and Fragment sit in the Select menu. Click Select once to use it, then click it again to open the menu.
With a bond or ring tool active, hold Ctrl and drag on empty canvas. You get a selection box without leaving the tool.
Quick select actions#
Open the Select menu in the top bar. It has the same tools plus actions that pick atoms by rule.
- Select all, Deselect (Ctrl+Shift+A) and Invert selection (Ctrl+Shift+I).
- Select connected (Ctrl+Shift+C) grows the pick to whole molecules. Grow selection (Ctrl+Shift+G) adds the neighbours.
- Same as selection (Ctrl+Shift+S) picks every atom with the same element or label.
- Select all rings and Select heteroatoms.
- By element, Structure… (chain atoms, longest path, side chains, 3 to 8 membered rings, aromatic, charged), Stereo & labels… and Bonds….
Every action is also in the command palette. The shortcuts list shows the keys for the rest.
Move, copy and nudge#
- Move: drag any selected atom or bond, or drag inside the dashed box.
- Join two molecules: drag a selection so one of its atoms lands on another atom. The two atoms merge into one.
- Free move: hold Shift while you drag. This turns off snapping to guides and the grid, and stops atoms from merging.
- Copy by drag: hold Ctrl (or ⌘ on a Mac), press inside the selection and drag. The original stays put.
- Nudge: press the arrow keys to move the selection 1 screen pixel. Hold Shift to move 10 pixels.
Rotate, flip and resize#
When you select something, a dashed box appears with a round rotate handle. A badge shows the angle while you turn it. Corner handles resize the selection.
Small buttons also float above the selection. They flip it left to right, flip it top to bottom, make a copy, or delete it. On a phone the buttons show the words Flip ↔, Flip ↕, Copy and Delete. An extra Actions button opens the rest of the menu.
Align and distribute#
Select two or more separate molecules or objects. These buttons appear in the top bar:
| Button | What it does |
|---|---|
| Align left, Align right | Lines up the left or right edges. |
| Align on vertical centres | Lines up the centres in one column. |
| Align top, Align bottom | Lines up the top or bottom edges. |
| Align on horizontal centres | Lines up the centres in one row. |
| Distribute horizontally, Distribute vertically | Makes the gaps even. |
| Arrange | Puts everything in one neat row with even gaps and aligned centres. |
The Generate menu beside them copies the selection in a circle, a line, a grid or a dendrimer. On a phone, tap Arrange to open the same buttons in a sheet.
Group molecules#
Select the molecules, right click and pick Group. A group moves as one unit when you drag any part of it. Pick Ungroup to split it again. Groups also show in the Objects list.
Delete#
Press Delete or Backspace, click the delete button above the selection, or use the Erase tool. Press Ctrl+Z to undo.
Common problems#
| Problem | Fix |
|---|---|
| Dragging moves the view, not the selection | You are on the Hand tool. Press V. |
| A copy was not made | Press inside the selection first, then hold Ctrl and drag. |
| Two molecules joined by mistake | Press Ctrl+Z, then hold Shift while you drag. |
| No align buttons | Select at least two separate molecules or objects. |
| Arrow keys do nothing | Nothing is selected, or you are typing in a text box. |
To tidy the drawing itself after you move parts around, see Clean up 2D and 3D. For touch gestures, see MolDraw on a phone or tablet.
Questions and answers
How do I duplicate a molecule in MolDraw?
Select it, hold Ctrl (or Cmd on a Mac) and drag from inside the selection. You can also click the copy button that floats above the selection.
How do I move a structure by a small amount?
Select it and press the arrow keys. Each press moves it 1 screen pixel, or 10 pixels with Shift held.
How do I flip a molecule horizontally?
Select the molecule and click the flip button above the selection. One button flips left to right, the other flips top to bottom.
How do I line up several molecules in a row?
Select them all, then click Arrange in the top bar. It places them in one row with even gaps.
Why did two molecules merge when I dragged one?
An atom of the dragged part landed on another atom, so they joined. Undo with Ctrl+Z and hold Shift while you drag to stop merging.
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