You can reverse an action by using the Undo command. Undo steps back one step at a time through the sequence of previous revertible operations. All commands that change model state can be undone, except for special exceptions which make changes too large to be undone. Model commands that cannot be undone display a warning, which must be dismissed. Commands that change only the user interface state cannot be undone. They can be mixed with model commands, but they do not undo or redo as you steps backwards and forwards through prior actions. You can view a list of irrevertible commands in the Command History viewport.
NOTE: The maximum number of revertible steps can be specified in the Preferences.
To Undo a step, press Ctrl/Cmd+Z, or in the menu bat, select Edit > Undo.
To Redo a step, press Ctrl/Cmd+Shift+Z) or in the menu bat, select Edit > Redo.
Modo provides a special memory buffer for temporarily holding data referred to as the clipboard. A clipboard is a useful function when moving data around from layer to layer and scene to scene. Modo adheres to the standard Cut, Copy and Paste methodologies universal to nearly all Windows and Macintosh applications. You can use the commands to manipulate text or numerical values when working in data input fields, or with geometry when working in the GL viewports.
Elements in the clipboard cannot be saved directly and are cleared from memory when Modo quits. Text and numerical data is not application-specific and can travel in and out of Modo. Any geometric data stored in the clipboard is relevant only to Modo. This is because each data type has its own buffer. Alphanumeric characters are copied to the system clipboard, while geometric data uses a Modo-specific clipboard.
The Modo geometry clipboard only stores component geometry data. Other item types such as Cameras and Lights cannot be stored in the clipboard. Whatever is selected and cut/copied is what gets pasted except with edges; when cut/copy/pasting edges the result is polylines (two point polygons) and not true edges because edges cannot exist without a polygon. These polylines can be selected in both the Edges and Polygons Selection modes. When selecting elements in Items mode, cut/copy/paste works on all component types at once and paste them in the same state as how they were cut/copied. The clipboard support all associated Vertex Maps and tags as well, so cut/copy/paste retains selection sets, material/part tags and when pasted into a different scene, related material surfacing comes along for the ride as well.
To use, user need only to make a selection of some type and then invoke the command from the menu bar under Edit, or by using the associated keyboard shortcut.
Cut: (Ctrl/Cmd+X) This option removes the selected element and stores it in the clipboard.
Copy: (Ctrl/Cmd+C) This option copies the selected element, leaving the original in place and stores it in the clipboard.
Paste: (Ctrl/Cmd+V) This option inserts the contents of the clipboard into the target layer or field.
TIP: When managing large scene files, or files with multiple layers, the 'Import' option may be more easier to transfer multiple layers simultaneously.
The Delete command applies to any type of selected data. For geometric data this is exactly like the cut command removing the data except that it is not moved to the clipboard. Deletion of vertices removes the vertices, but leaves any remaining vertices/polygons (if applicable). If all the vertices of a polygon are deleted, then the polygon itself is removed. Deletion of polygons also deletes the associated vertices if they are not needed for any other polygons that stays behind. Deleting an edge removes any adjoining polygons leaving a hole. When in Items mode, deleting an item removes the layer, including all geometry contained within from the Item List. When text is selected in an input field, delete removes the selected section.
Delete: (Delete key) Deletes the selected element from the scene entirely.
Remove is effectively the same function as Delete, however the one notable difference is that when working with edges, removing them eliminates the edge itself, but leaves the neighboring polygons in place essentially resulting in a polygon merge, joining the neighboring polygons.
Remove: (Backspace key) Removes the selected element from the scene.