How to create 3D Dimensions in just 3 steps using Mech-Q

How to Create Accurate 3D Dimensions in AutoCAD-Compatible CAD

(Using Mech-Q or AViCAD)

Dimensioning in 3D CAD has traditionally been a frustrating process.

In standard 2D drafting, dimensions are straightforward because everything lives on a flat plane. The User Coordinate System (UCS) remains aligned with the X and Y axes, making dimension placement predictable and easy.

In 3D, however, things change.

To dimension accurately, the UCS must be rotated and aligned with the object’s working plane. Dimensions must be oriented correctly in X, Y, or Z space, and even slight misalignment can cause them to display incorrectly in 3D. Rotating objects and dimension text across multiple axes only adds to the challenge.

For many users, this leads to repeated trial-and-error, redimensioning, or even skipping 3D dimensions altogether.

A Simpler Way to Dimension in 3D

Mech-Q introduces a dedicated 3D Dimension tool that removes the complexity entirely.

This tool automatically handles UCS orientation, axis alignment, and dimension placement behind the scenes — allowing you to dimension pipes, fittings, piping spools, or any 3D object as easily as placing two points.

The 3D Dimension tool is included with Mech-Q and also available in AViCAD, our AutoCAD-compatible CAD platform. It works seamlessly in AutoCAD and AViCAD alike.

Watch: 3D Dimensioning in Action

In the video above, you’ll see how quickly 3D dimensions can be created — without manually setting or rotating the UCS.

3 Steps to Creating a 3D Dimension

Step 1 — Set Your View

Switch to a 3D isometric view.
Turn on Center and Node object snaps, and enable Polar Tracking, as shown in the video.

If the two points you’re dimensioning are aligned on the same axis (co-linear), simply pick the two points and press Enter (or right-click).

Step 2 — Handle Non-Co-Linear Points

If the points are not aligned on the same axis, enter four points total:

1. The first two points define the working axis
2. The remaining two points define the actual dimension measurement

Once the points are selected, press Enter (or right-click) to complete the dimension.

Step 3 — Edit the Dimension (Optional)

After placing the dimension, you can fine-tune it directly within the command:

• Mirror or flip the dimension text
• Rotate the dimension orientation
• Move the dimension to a new position

All edits happen on the fly, without restarting the command.

Why This 3D Dimension Tool Is Different

• Dimension any 3D object at any angle
• Automatic UCS orientation
• Simple two-point selection
• Works on sloped and rotated objects
• Edit dimensions instantly (Rotate, Flip, Mirror, Move)
• One-letter command shortcuts for fast adjustments
• Included with Mech-Q and AViCAD (our AutoCAD alternative)
• No manual UCS setup.
• No trial-and-error dimension placement.
• No redrawing dimensions multiple times.
  
  

Who This Is For

• Mechanical detailers working in 3D
• Piping spool drawings
• Fabrication and layout drawings
• Anyone frustrated with traditional 3D dimensioning workflows

If you’ve ever resorted to measuring distances manually or skipping dimensions because they were too time-consuming, this tool was built for you.

Get Started

You can try the 3D Dimension tool today as part of Mech-Q or AViCAD.

There’s no obligation to test the software — download a free trial and see how much faster 3D dimensioning can be.