1.4 Using the Sketch Tools

Sketch Toolkit

Available with the Following Subscriptions: All Subscriptions
Available for the Following Roles: All Roles

This user guide article shows how to utilize the Sketch Tool, a fundamental tool for creating geometries in cmBuilder such as linear resources, 3D lines, zones, massing, and excavation.

Starting a New Sketch

Several tools in cmBuilder use a Sketch as a reference. Once you reach the step to create your sketch within these tools, your cursor will change to a pen (1) and a new side sheet menu (2) will appear.

Starting the Sketch 1.png

Your first click will define the origin (1) and elevation (2) of your sketch which, depending on the tool you are using, can be placed at the terrain elevation, on top of buildings and massings, or adjusted manually in the input field.

Starting the Sketch 3.png


Polyline Features

  1. The default selection is a line. Choose to draw a line, arc, circle, or rectangle from the available toolset options.
  2. From the side sheet, you can pick your preferred sketch surface. The option is available to stick with the default Z-plane or select a Custom plane according to your needs.

Frame 244790.png

How Polylines work

  1. Clicking an object (e.g. 3D Line, massing, zones, creating fence etc.) that references a Polyline,  activates a pen cursor on the screen.
  2. The default tool is the line, and a click positions the initial point on the plane.
  3. Subsequent clicks create lines, allowing you to add points and form either a continuous line or a closed polygon.
    • 💡TIP: Turn on the "Close Polyline Automatically" toggle under settings to create a closed polygon.
  4. Click "Confirm" or press "Enter Key" to complete the sketch profile. 

Frame 3.png


The polyline tool has a handy toolkit that make it easier to create complex shapes by using sketch constraints.

The table below provides a description of the various polyline sketch tools.

Sketch Tools


IconButton (12).svg Line

Upon entering, the line tool is pre-selected and is used to draw a straight line.

IconButton (9).svg Arc
Create a line to enable the arc tool. Adjust the arc's size by moving the cursor: closer for a smaller arc, farther for a larger arc. Click again to finalize the shape.
IconButton (10).svg

Click and drag outwards to draw the circle. Click again to finalize the shape.

IconButton (11).svg

Click to place the first corner, then click again to place the opposite corner. Note: the rectangle will be rotated based on your object's rotation, typically oriented to the north.

The following table provides a description of the polyline editing tools.

Toolkit Button


move.svg Move
Use this to move points or lines. Once activated, a move cursor appears on the screen. Now you can move the points and/or line to alter the geometry. 
IconButton (2).svg Redraw
Use this to edit the existing sketch. This action erases the current sketch, then start fresh with your edits.
IconButton (1).svg Project from 3D
This replicates the sketch onto any object in the site plan by projecting it onto the closest surface. To proceed, select the desired object to project onto.
IconButton (3).svg Snap to face
Use this to easily snap a selected a point or line to the face of any existing object within your site plan. 
IconButton (5).svg

Offset Sketch
This enables the creation of a new sketch at a specified distance from the original. Simply select the curve to offset, then drag the cursor outside or inside the original sketch.

Alternatively, enter the offset distance from the right side sheet while keeping the cursor in either direction.

IconButton (6).svg Perpendicular
Use this to make two lines at right angles. Pick the first line, then choose the reference line. Result, two lines that are now perfect 90° angle to each other.
IconButton (7).svg Parallel
Use this to make two lines parallel. Just select the line to move, then select the reference line. Result, two lines that are now parallel to each other.
IconButton (8).svg Equal
Use this to make two lines of equal length. Simply select the line to adjust, then choose the reference line. Result, two lines that are now equal in length.


Using Hotkey constraints 

Constraints are applied during sketching by holding down the Shift key on your keyboard, shaping the drawing process. When Shift is pressed, it restricts straight lines at the axis, aligning them precisely with multiples of 45°. This ensures accurate and angled sketching for greater precision.
Frame 5.png

Polyline Side Sheet

The side sheet has two tabs: Properties and Settings

Properties Tab

In the Properties tab, you can find various options related to the sketch surface and geometry type:

  1. Sketch Surface: Choosing the sketch surface is easy from the side panel. Stick with the default Z-plane or opt for a custom plane according to your needs.
  2. Plane Offset (2a): On the side sheet, input the plane offset. This creates the sketch below/above the main plane when you enter a desired value here. 
    • Select offset from 3D Viewer (2b): The icon button on the right allows selecting the offset directly from the 3D viewer, providing greater control and accuracy.
      Frame 6.png

    • After placing the first point, the side sheet undergoes updates, and certain fields, initially disabled, become enabled based on specific actions.
  3. Length (3a): When a line is selected, the length input is enabled, allowing for the input of a desired length.
    • Flip Direction (3b): The icon button on the right is for flipping the line direction. This means that after entering the length, using the icon button allows the direction of the line to be switched.Frame 9.png

  4. Angle (4a): Upon selecting a point between two lines, the angle field becomes enabled for value input.
    • Flip Direction (4b): The icon button on the right serves to flip the angle. While entering the angle, one of the lines adjusts accordingly. Yet, utilizing the icon button enables changing the direction of the line after entering the new angle.
  5. Point: The point includes Vertical (5a) and Horizontal (5b) values that can be updated as needed.
  6. Sketch Area: This shows the area enclosed between the sketch lines.Frame 8.png

Settings Tab

In the Settings tab, you can find various options related to the display of sketch lines :

Frame 4.png

  1. Close Polyline Automatically: When turned on, this makes a closed polygon when a minimum of two lines are drawn. 
  2. Length: Activating this option displays a length tag Default.svgalong the line.
  3. Angle: Enabling this option shows an angle tag default (2).svg, indicating the angle between two lines.
  4. Area Preview (4a): When selected, this feature presents an enclosed area preview with a yellow-tinted shade among the lines.
    • Snapping (4b): A red dashed axis is displayed when the line aligns with local coordinates (X, Y, Z, Real North).

  5. 3D Projection (5a): When activated, a green line appears on the closest surface, representing the visual projection of the original sketch in 3D space.
    1. Guiding Line (5b): This option introduces a blue dashed line connecting the original sketch and its projected counterpart.

Sketch Projection

You can use the “Project from 3D” tool to utilize sketches from existing geometries like imported models or resources created with a polyline. See the following video to learn how.

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