How to: create a 3D Sketch building in Forma Site Design

Forma Site Design, available in the AEC Collection or as a standalone subscription, offers powerful AI-powered tools for architects and designers in pre-design and schematic design phases.

Create and refine a 3D massing model in Forma Site Design using 3D Sketch, then convert it into a building with defined floors and functions.

Step 1: Create a basic 3D shape

1. Launch 3D Sketch by click the New 3D Sketch button in the Design toolbar.
2. Use the Cuboid tool from the 3D shapes menuto draw a 40’ cube.
3. Select a face and click again to extrude it by 100’.
4. Repeat the same action in the perpendicular direction to create a square footprint for your 3D volume.

Step 2: Design your 3D volume

Extrude faces

1. Use the Line tool to draw lines that start and end at edges, to split the roof into two surfaces.
2. Select one of the split surfaces and click again to extrude it downward through the volume.
3. Apply the same technique to vertical surfaces.

Pro tip: Use edge midpoints for accuracy when drawing lines.

Add a pitched roof

1. Use the Line tool to split part of the roof into a square or rectangle.
2. Select the split surface and extrude it up by 20′.
3. Draw a line on the surface that represents the ridge of the pitched roof.
4. Select the roof edges that are parallel to the ridge line.
5. Use the Move tool to move the selected edges downward along the Z axis and snap to the rest of the roof.
   • Pro tip: Hold Shift to lock the movement direction.

Add an asymmetrical angled roof

1. Use the Line tool to split part of the remaining flat roof into a square or rectangle.
2. Select the outer edge of the split surface and extrude it upward along the Z axis.

Add a curve

1. Start the Arc by three points tool from the Sketch menu in the toolbar.
2. Set the first two points to intersect with roof edges.
3. Set the third point to define the curve.
4. Select the surface outside the arc and extrude it downward to the desired level.

Step 3: Convert your 3D volume into a 3D Sketch Building

1. Click the plus icon next to Add floors in the right panel.
   • Lines will appear on the 3D volume to indicate how he default floor heights stack up on your design.
   • Your Generic 3D Sketch is now a 3D Sketch Building.
2. Adjust the number of floors, default floor height and height of individual floors in the Floors section in the right panel.
3. Review the building’s Area metrics in the right panel.
   • Area metrics are only calculated for Buildings within a Site Limit.

Step 4: Assign floor Functions

1. Exit 3D Sketch by pressing Esc or the X in the toolbar.
2. Select one or more floor volumes.
3. Tag your selection with a Function from the Right panel.
4. Expand the Gross Floor Area under Area metrics to view the breakdown by function.