How to Create MEP Models in BricsCAD BIM

Quick answer: MEP modeling combines BIMAPPLYPROFILE, BIMLINEARSOLID, BIMFLOWCONNECT, DRAG, and BIMSTRETCH, both covered and confirmed against this hub’s BIM linear solids page, to draw and connect flow segments like ducts and pipes.

Connecting Segments with BIMFLOWCONNECT

Select the segments you want to connect and launch BIMFLOWCONNECT.
With the Hotkey Assistant switched on (HKA on the Status Bar), a widget appears; press Ctrl to cycle through the connection options.
Press Enter to finish; the segments connect.

Altering the Position of Segments

Before starting, enable selection of sides and ends: click the icon on the Selection Modes toolbar, or set DISPLAYSIDESANDENDS on, the same variable covered on this hub’s BIM linear solids page.

Using DRAG (alters a segment of a drawn profile without losing its connection to the others):

Hover over a segment and select a face perpendicular to the profile’s section.
Launch DRAG.
Choose a new position, or type a displacement value in the dynamic dimension field; BricsCAD automatically regenerates the connection between segments.

Using the Manipulator:

Hover over a segment and select a face perpendicular to the profile’s section.
Choose Manipulate.
Choose a new position, or type a rotation value in the dynamic dimension field.
Click the new position, or type the rotation angle and press Enter.

Drawing and Connecting Profiles: A Worked Example

An example MEP drawing file is downloadable directly from Octave’s documentation for this article.

Open the drawing containing the MEP model.
Open the BIM Profiles panel, filter on HVAC, select the Rectangular 12″x8″ profile, and drag it into the model space.
Define the profile’s starting point by snapping to the geometric centre of the yellow rectangle.
With Ortho on, define the next points using the dynamic dimension field (typing Q performs a quarter turn): go up 3.5, left 3.5, then horizontally 21.

Note: drawing with a non-HVAC profile skips automatic Flow Segment classification; classify it manually with BIMCLASSIFY as Building Service Elements – Flow Segments instead.

Select the side ducts together with the main duct you just created and launch BIMFLOWCONNECT to connect them.
Create a duct from the flow terminal: launch BIMLINEARSOLID and select the flow connection point; since it carries profile information, BricsCAD automatically creates the predefined circular duct. Give it a length of 1.
Select the main duct and the duct from the flow terminal, then launch BIMFLOWCONNECT to connect them.
Select every remaining flow terminal along with the rectangular duct, and launch BIMFLOWCONNECT once to connect them all at the same time.
BricsCAD uses the flow connection point’s information to determine which duct type connects to the main duct (in this example, the terminal at the back connects to the back of the rectangular duct).

Altering Profiles: A Worked Example

Type XREF at the Command line and tick the load box next to the structural model to load it.
Use SLICE with the Multislice option to divide the rectangular duct: type 3 in the dynamic dimensions field and press Enter to finish.
Reposition the duct so it doesn’t interfere with the structural model: select its upper face and launch DRAG, then move it down 0.23. BricsCAD preserves its connections with the circular ducts (hold Ctrl if you want to disconnect them instead).
The structural model no longer interferes with the MEP model, and the connections between the flow terminal ducts and the main rectangular duct stay intact. Moving a flow terminal with the Manipulator similarly keeps its connections with flow segments intact.

Using BimStretch to Modify Flow Segments: A Worked Example

Open a new drawing.
Open the BIM Profiles panel (if its icon isn’t visible, right-click the ribbon and tick BIM Profiles in the context menu).
Filter on the HVAC standard; these profiles classify automatically as flow segments once dragged into the model space.
Search for HVAC Rectangular Duct 10”x10” in the panel and drag it into the model space.
Select a starting point and draw a profile, pressing Enter to stop.
Search for HVAC Round Duct 8” and drag it into the model space too.
Click the end of the rectangular profile after hovering over its face. Turn on Display Axes (DISPLAYAXES set to 1, the same setting confirmed on this hub’s BIM linear solids page) to snap to that end more easily.
Draw the circular profile along the same axis as the rectangular one; accepting its last point connects it to the rectangular profile automatically through a generated reducer. A non-HVAC profile skips both the automatic classification and the connection, classify it manually with BIMCLASSIFY, then connect it through a reducer with BIMFLOWCONNECT. Make sure Display Sides and Ends and Display Axes are both enabled.
Select the connecting ends of both segments.
Launch the BimStretch tool.
Hover toward one of the sides and click the location you want; BricsCAD automatically stretches both flow segments into their new position, adding an extra curved Flow Fitting in the middle.

Frequently Asked Questions

What happens if I draw a duct profile that isn’t from the HVAC standard? It won’t automatically classify as a Flow Segment or connect automatically, you’ll need to classify it manually with BIMCLASSIFY and connect it with BIMFLOWCONNECT.

Does moving a duct with DRAG break its existing connections? No, connections regenerate automatically, unless you hold Ctrl to disconnect them intentionally.

What setting makes it easier to snap to the end of a duct profile? Display Axes, set via DISPLAYAXES = 1.

What does BimStretch actually do when connecting two flow segments? It stretches both segments into their new position and automatically adds a curved Flow Fitting between them.