How to Use Propagate Planar in BricsCAD BIM

Quick answer: This worked example shows BIMPROPAGATEPLANAR propagating a detailed wall-slab connection to every similar location in a model, confirming the general two-step Propagate workflow covered elsewhere in this hub, along with a genuine failure case and how to resolve it.

Setting Up the Connection Detail

Start with four walls and one slab, created with QuickDraw (the same tool covered on this hub’s BIM Quickdraw page). Give all four walls and the floor slab a composition. Without further editing, a vertical section through the building at this point shows a “cold,” unconnected joint between a wall and the slab.

While that section stays active, Push/Pull the different ply faces (the same technique covered on this hub’s connecting solids and BIM ply editing pages) to shape the connection you actually want between the wall and slab. Detail it further if you like, for example by drawing a box and classifying it as a Building Element to add a skirting board.

Propagating the Connection

1. With this detailed connection in place, deactivate the section and launch BIMPROPAGATEPLANAR.
2. You’re prompted to select the planar reference solids forming the connection; select the wall and slab, then press Enter.
3. You’re prompted to optionally select detail objects to copy along with the connection; select the skirting board and press Enter.
4. A genuine failure case can occur here: if the skirting board wasn’t modeled along the entire length of the wall, you’ll see “The detail section varies too much along the extrusion direction,” BIMPROPAGATEPLANAR can’t find a solution, because it finds contradicting detail volumes at different points along the wall. Fix this by activating a section where the skirting board actually is present (the same section used to originally create the detail works well) and trying again; this time a proper detail volume is found.
5. You’re prompted whether to accept the detail volume: Yes, No, Inflate first, Save detail, or save detail to Library (inflating isn’t needed for this example; see this hub’s general Propagate page for more on that option). Press Enter to accept.
6. BIMPROPAGATEPLANAR scans the entire drawing for similar locations; every section deactivates, and the view zooms out to show all the possible suggestions, each with a widget, the same icon system covered on the general Propagate page. A question mark widget, for example, might reveal on hover: “Location of original detail. Click to replace original detail by adapted extrusion.” Since the skirting board was only modeled locally in this example, clicking that widget replaces the original with an adapted extrusion covering the wall’s entire length.
7. Press Enter to complete the command; all four walls now share this connection with the floor slab, skirting board included.

Frequently Asked Questions

What does “The detail section varies too much along the extrusion direction” actually mean? BIMPROPAGATEPLANAR found contradicting detail volumes because the detail (like a skirting board) wasn’t modeled consistently along the entire length of the reference solid.

How do I fix a detail volume that fails to generate because of an inconsistent detail? Activate a section where the detail is actually present, typically the same one used to create it originally, then retry.

What does the “Location of original detail” widget option do? It replaces a locally-modeled detail with an adapted extrusion, extending it to cover the full length of the reference solid rather than just where it was originally drawn.

Do I need to inflate the detail volume for a straightforward wall-slab connection like this? Not necessarily, this example didn’t require it; inflating is more useful in specific situations covered on this hub’s general Propagate page.