How to Use BIM Sections in BricsCAD BIM

Quick answer: _SectionSettings.dwg (containing every type of section callout) drives BIM section creation, located at C:\Users\%username%\AppData\Roaming\Bricsys\BricsCAD\V26x64\en_US\Support\Bim\Sections, confirming the exact same Support folder structure covered on this hub’s BIM tags page. Its section entity templates use hard-coded names (_Section, _Elevation, _Plan, and so on), used by BricsCAD to identify which template to apply defaults to, these names should never be changed.

Defining a Section

The Define Section tool creates BIM section entities that section a BIM model by a plane and reveal interior details. A section tracker attaches to the cursor: the section plane lies in the XY-plane of the current coordinate system (WCS or UCS), and the view direction is that system’s negative direction. With Dynamic UCS (DUCS) on, the section plane aligns to whatever 3D solid face is under the cursor (press Tab for an obscured face); press Shift to lock a highlighted plane, letting you specify a definition point outside that face. The section line stays parallel to the coordinate system’s X-axis.

General procedure:

1. Choose Define Section on the Model tab of the No Selection Quad.
2. Either click a point anywhere outside the model for a plan section, or hover over a 3D solid face parallel to the plane you want (DUCS must be active for it to align), then left-click; optionally press Shift first to lock the plane and start from a point outside that face.
3. The initial section plane displays dynamically, clipping the 3D model accordingly. Either type a value in the dynamic dimension field to offset it from its initial position, or left-click when it’s where you want it; the BIM Section entity defines.

Which template gets used depends on the plane’s direction and whether it intersects the model: Plan for a horizontal plane, Section for a vertical plane cutting through the model, and Elevation for the exterior elevation view.

Creating a Plan Section

Best defined in the WCS.

1. Choose Define Section on the Model tab of the No Selection Quad.
2. Place the tracker near the model and click; the initial plane sits in the XY-plane (Z = 0) of the current coordinate system, and the model clips dynamically as it displays.
3. With Dynamic Dimension on, the current distance shows in a dynamic field. Either move the cursor and click at the desired height, use an entity snap to specify a point, or type an offset value; the plan section defines.

Creating a Cross Section

Make sure Dynamic UCS (DUCS) is on.

1. Choose Define Section on the Model tab of the No Selection Quad.
2. Place the tracker over a 3D solid face parallel to the cross-section you want.
3. Click once the face highlights and move the tracker inside the model; the plane displays dynamically, clipping the model accordingly (the current distance shows in a dynamic dimension field if Dynamic Dimension is on).
4. Click at the desired location, or specify a distance; the cross-section defines.
5. Optionally click the section entity and hold the left mouse button slightly longer to display the Manipulator, then drag an axis to move the section.
6. Optionally click the Arrow grip to flip the view direction.

Creating an Elevation

Make sure Dynamic UCS (DUCS) is on.

1. Choose Define Section on the Model tab of the No Selection Quad.
2. Place the tracker over a 3D solid face parallel to the elevation you want and click once it highlights.
3. Move the tracker outside the model and click to define the elevation. Vertical sections placed entirely outside the model, with no geometry actually sectioned, automatically get the Elevation template.

Editing the Default Properties of a BIM Section

A BIM section’s default properties copy from the section entities in _SectionSettings.dwg. Select the section (in the drawing or Structure panel) to edit its properties.

Section Entity properties: Name; Type (Plane, the default, Boundary, Volume, or Slice, determining how the result clips); Live section (only one section entity can have this on at a time, using Clip display instead is recommended, since Live section is meant for visual checking only, not 3D modeling); Clip display (multiple entities can have this on simultaneously, and unlike Live section, entity snaps remain available in the section plane); Use lids (closes the top faces of clipped geometry); Section offset (position relative to the clipped geometry); Slice thickness (Slice type only); Plane transparency and Plane color (for rendered Visual Styles); Destination file (the name and path BIMSECTIONUPDATE saves to, defaulting to the 3D model’s own folder if unspecified).

Geometry properties: Elevation (the Z-value of the section plane’s start point); Top plane and Bottom plane (bounding the section volume); Vertex (control point coordinates, 2 for Plane type, 4 for Boundary, Volume, and Slice types, select the field and use the arrow buttons to cycle through them, an X marks the currently selected vertex in the model); UCS Elevation (minimum and maximum values).

BIM properties: Name, Description, Building, Story; Initial scale (of the paperspace viewport in the generated drawing); Layer state (used to calculate the section) and Apply layer state (whether it’s actually used, letting you control which layers are on or off when calculating the result); Project section (controls section callout and line display in perpendicular section drawings); Use section plane orientation; Entity property sets (whether per-instance entity properties can generate tags, click Browse to select property sets in the Enable per-instance property set dialog).

Toggling Clip Display

Clip display temporarily clips 3D models, usable during any modeling or editing operation on any drawing content, and multiple section entities can have it on at once, even facing opposite directions (a plan section and a reflected ceiling section, for example).

Toggle it by double-clicking the section entity, choosing Clip display from the Quad, selecting the section plane and setting Clip display to Yes in the Properties panel, or hovering over the section entity with RT (Rollover Tips) enabled on the Status Bar. Optionally set the current section’s Type property to Volume in the Properties panel to display the clipped result as a volume.

Converting a Section Entity to a BIM Section Entity

BIMIFY converts a plain section entity into a BIM section entity.

1. Launch BIMIFY; the Bimify command panel opens.
2. Choose Select entities in drawing and click Select.
3. Select the section entity and press Enter.
4. Click Apply in the Bimify command panel.

Frequently Asked Questions

Why shouldn’t I rename the section entity templates in _SectionSettings.dwg? BricsCAD uses their hard-coded names (_Section, _Elevation, _Plan, and so on) to identify which template to apply default values to; renaming them breaks that lookup.

What’s the difference between Live section and Clip display? Only one section entity can have Live section on at a time, and it’s meant for visual checking only. Clip display works on multiple entities simultaneously and keeps entity snaps available, making it the recommended choice for 3D modeling.

How does BricsCAD decide whether a section becomes a Plan, Section, or Elevation? Based on the plane’s direction (horizontal or vertical) and whether it actually intersects the model; a vertical plane placed entirely outside the model automatically becomes an Elevation.

Can I convert a regular section entity into a BIM section entity after the fact? Yes, select it and run BIMIFY.