View Manipulation with the Mouse and Keyboard in BricsCAD
Quick answer: BricsCAD lets you navigate a 3D model entirely with the mouse and keyboard, panning, zooming, rotating, and walking through it. In perspective mode you can walk inside the model; in isometric mode you can only zoom in close, not actually move inside it.
Perspective vs Isometric Mode
Perspective mode lets you walk inside the 3D model itself. Isometric mode doesn’t, you can zoom in very close, but you can’t go inside.
Mouse Wheel Zooming
Scrolling the mouse wheel zooms in or out. The increment per scroll is set by ZOOMFACTOR (default 60, accepting values from 3 to 100), and that increment decreases gradually as you zoom in, making it easier to home in on fine detail. In a 3D model, whatever entity is under the cursor gets the zoom focus.
ZOOMWHEEL controls the direction: at 0 or off (the default), scrolling forward zooms in and backward zooms out; at 1 or on, that’s reversed, forward zooms out and backward zooms in.
View Manipulation Shortcuts
| Mouse or keyboard | Action | Result |
|---|---|---|
| Middle mouse button or wheel | Hold and move | Real-time pan (RTPAN) |
| Middle mouse button or wheel | Double-click | Zoom extents |
| Ctrl+Shift+Left mouse button | Hold and move | Real-time zoom in/out (RTZOOM) |
| Ctrl+Shift+Right mouse button | Hold and move | Constrained real-time pan (RTPAN); release Shift for free panning |
| Ctrl+Shift+Middle button or wheel | Hold and move | Real-time sphere (RTROTF) |
| Shift+Middle button or wheel | Hold and move | Real-time constrained sphere (RTROT) |
| Ctrl+Right button | Hold and move | Real-time rotation about the screen Z-axis (RTROTZ) |
The middle mouse button shortcuts above require MBUTTONPAN to be set to on.
Walk-Through Navigation Shortcuts
| Mouse or keyboard | Action | Result |
|---|---|---|
| Alt+Left button | Hold and move | Walk left/right and forward/backward (RTWALK) |
| Alt+Middle button | Hold and move | Move up/down and left/right (RTUPDOWN) |
| Ctrl+Middle button | Hold and move | Look around (RTLOOK) |
| Ctrl+Arrow keys | Hold Ctrl, press arrows | Walk left/right and forward/backward (RTWALK) |
| Ctrl+Shift+Arrow keys | Hold, press arrows | Look up/down and left/right (RTUPDOWN) |
Home |
Sets the view direction to horizontal (VIEWHORIZONTAL) |
|
Alt+Home |
Moves the target point to the centre of the scene | |
| Alt+plus/minus | Increases or decreases movement speed | |
| Ctrl+plus/minus | Increases or decreases rotation speed |
Note: Octave’s own documentation lists the “look up/down and left/right” shortcut inconsistently, the table itself labels it Ctrl+Shift+Arrow Keys, but the accompanying description text says to hold Alt+Ctrl instead. These are genuinely different key combinations, not just inconsistent wording, so if one doesn’t work as expected, try the other.
Frequently Asked Questions
Can I walk inside a 3D model in isometric view? No, only in perspective mode. Isometric mode lets you zoom in very close, but not actually move inside the model.
Why does scrolling the mouse wheel zoom out instead of in? Check ZOOMWHEEL. At its default (0 or off), scrolling forward zooms in; set to 1 or on, that direction reverses.
What’s the difference between constrained and free real-time panning? Holding Ctrl+Shift+Right mouse button gives constrained real-time pan; releasing Shift while still holding the rest switches it to free panning.
Do the middle mouse button shortcuts always work? Only if MBUTTONPAN is set to on. If they aren’t responding, check that setting first.