How to Use Propagate in BricsCAD BIM
Quick answer: BIMPROPAGATE maps a construction detail from selected reference solids to every similar location throughout the model. This finally resolves the command used repeatedly on this hub’s structural steel and connecting solids pages. Five specialized variants distill it for common use cases, anything solvable with a variant is also solvable with the standard command, though the standard command can solve problems no variant can.
The Five Variants
| Variant | What it propagates |
|---|---|
BIMPROPAGATEPLANAR |
Connections between planar elements, walls, slabs, and roofs |
BIMPROPAGATELINEAR |
Connections between linear elements, beams, columns, pipes, and ducts, plus at most one planar element |
BIMPROPAGATEPATTERN |
A single element or group on a flat surface to multiple locations and grids, light fixtures, switches, windows, air diffusers, or columns on a grid |
BIMPROPAGATEEDGES |
A detail along the edge of a planar solid, railings, gutters, borders, wall caps |
BIMPROPAGATECORNER |
Details connected to multiple planar reference solids meeting at one node |
Step 1: Defining the Detail Volume
Reference solids: you’re prompted to select reference solids first, entities that won’t be copied but are used to match similar situations elsewhere in the model. For a column-beam connection with an end plate and bolts, the reference solids are the column and beam themselves. Press Enter to stop selecting.
Detail objects: next, optionally select the objects to actually copy, solids, block references, or even individual faces (propagating a hole in a reference solid, for example, by selecting its faces). In the column-beam example, the detail objects are the end plate and bolts. Sometimes no detail objects are needed at all, propagating a floor-slab-to-wall connection needs only the reference solids, so press Enter or right-click to skip this step.
Once both are specified, a detail volume defines automatically; the visual style temporarily switches to X-ray, and the view zooms in on it. Everything inside that volume, whether a detail object or part of a reference solid, gets copied to other locations. Worth knowing: holes in a reference solid that fall inside the detail volume get copied too, even if you never explicitly selected them as detail objects, BIMPROPAGATE does more than a simple copy.
A detail volume is either a full 3D volume, or a 2D slice through a linear detail (BIMPROPAGATEPLANAR and BIMPROPAGATEEDGES always use a 2D slice). You’re prompted to accept it, choosing yes copy as Block, yes plain Copy, No, Inflate first, Save detail, or save detail to Library (2D details are first asked whether to propagate as an extrusion of that section). For a 3D detail specifically, choosing Block groups every detail object into a new Block Definition and copies references to it around the model; Copy copies the actual entities instead.
The Inflate Feature
Usually the proposed detail volume is enough, but you can inflate it to include more, useful in two situations:
- Replacing an existing detail with a smaller one: inflate the volume so it’s larger than the original detail you’re replacing.
- Connecting solids that are further apart: for example, propagating a connection between a red and yellow beam so the yellow and green beam get the same connection, inflate the volume so it overlaps the end faces of both beams involved.
Step 2: Choosing Where to Apply the Detail
The view zooms out to show every possible location the detail could apply to, each marked with one of five icons:
| Icon meaning | Result |
|---|---|
| Apply | The detail will be applied |
| Do Not Apply | Won’t be applied, manually toggled off |
| Ask | Won’t be applied, for one of several reasons, hover for details |
| Apply with Remarks | Will be applied, but interferences were detected |
| Apply with Options | Will be applied, but several alternatives exist, hover to cycle through them |
Hover a widget for more information; click it to toggle its status. Press Enter to apply every suggestion currently showing a checkmark.
Widgets can also be selected with a window selection (a selected widget shows a blue border); with one or more selected, pressing Enter applies only those selected suggestions instead of all of them, a useful way to work through suggestions gradually: select and toggle off a batch, press Enter to remove them from view; select another batch you want applied, press Enter to apply and remove them; repeat until every suggestion is resolved, the command ends once the last one is handled.
BIMPROPAGATE only processes entities that are currently visible, hidden entities or those on a hidden or frozen layer are excluded from the scan entirely. In a large model, turning on only the relevant layers (steel members only, for a steel connection, for example) improves propagation performance significantly.
You can also activate or move an existing section plane during propagation: double-click it to activate, left-click once to move it. An active section plane may show a widget indicating hidden suggestions exist because of it, click that widget to deactivate the section and reveal them.
Frequently Asked Questions
Can I solve a propagation problem the specialized variants can’t handle? Yes, the standard BIMPROPAGATE command can solve problems none of the five variants can, they’re distillates designed for common use cases specifically.
Do I always need to select detail objects, or just reference solids? Not always, some situations (like a floor slab to wall connection) only need reference solids, skip the detail objects step by pressing Enter or right-clicking.
Does propagating a detail with holes in the reference solid copy those holes automatically? Yes, if they fall inside the detail volume, even without being explicitly selected as detail objects.
How do I improve BIMPROPAGATE’s performance in a large model? Turn on only the layers relevant to what you’re propagating, since hidden and frozen-layer entities are excluded from the scan entirely.