3DDISTANCE command in AutoCAD : Starts the interactive 3D view and makes objects appear closer or farther away

If you need to measure true 3D distances in AutoCAD—between points at different elevations or on different objects—the 3DDISTANCE command is built for that. This guide explains what 3DDISTANCE does, how to use it step‑by‑step, common reasons it may fail and how to fix them, alternative methods to measure distances, practical tips, and a FAQ section to answer likely follow‑up questions.

What is the 3DDISTANCE command?

The 3DDISTANCE command in AutoCAD measures the true 3D distance between two points in Model space. Unlike the 2D DIST command, 3DDISTANCE reports the full 3‑axis vector information: ΔX (DX), ΔY (DY), ΔZ (DZ), the 3D distance, and the relevant angles (planar angle and elevation/vertical angle). This makes it the right tool when you need accurate measurements in 3D models or drawings with varying Z elevations.

When and why use 3DDISTANCE?

• When you need the exact spatial distance between two points that are not on the same Z plane.
• To obtain component distances DX, DY, DZ for calculations (cut/fill, fabrication, machining).
• To check true lengths of tilted lines, edges of 3D solids, or endpoints on different elevations.
• To verify model geometry between vertices, faces, or anchor points.

How to use 3DDISTANCE (step-by-step)

1. Activate the command:

   • Type 3DDISTANCE (or 3DDist) at the command line and press Enter.
   • Or use the ribbon: Home tab → Utilities panel → Measure → Distance (then choose 3D mode if available).

2. Specify the first point:

   • Click in the drawing or type coordinates (e.g., 10,5,3).
   • Use Object Snaps (Endpoint, Intersection, Nearest) to pick exact points on objects.

3. Specify the second point:

   • Click the second point or enter coordinates (e.g., 13,9,-7).
   • Again, use object snaps for precision.

4. Read the results in the command line:

   • AutoCAD displays DX, DY, DZ, the Distance (3D length), and angle values.
   • Example output for point1 (0,0,10) and point2 (3,4,0):
     • DX = 3, DY = 4, DZ = -10, Distance = 11.18034 (sqrt(3^2+4^2+(-10)^2))

5. Optional: Use dynamic input or coordinate entry:

   • Enter exact coordinates; you can use relative coordinates with the @ symbol (e.g., @3,4,-10).

6. Use the From option (if available) to measure relative to a picked point:

   • This is useful for chaining measurements from a known origin.

Notes:

• Use the Osnap settings (F3) to ensure you pick exact geometry points.
• If you need multiple measurements, repeat the command or use the Measuregeom command with the Distance option.

Common 3DDISTANCE options and what they show

• DX / DY / DZ — the component differences between the two points.
• Distance — the true 3D straight‑line distance.
• Angle — planar or horizontal angle between the two points (depending on version/setting).
• Elevation angle — angle of rise or fall in 3D (shown in some AutoCAD outputs).

Examples (textual before/after)

Example 1 — Measuring between roof ridge and ground point:

• Before: you only know plan distance on XY = 5 m; Z difference unknown.
• Use 3DDISTANCE: pick ridge point (10, 20, 8) and ground point (12, 24, 0). AutoCAD returns DX=2, DY=4, DZ=-8, Distance = sqrt(4+16+64)=9.165.

Example 2 — Verifying length of a slanted beam:

• Select beam endpoints with object snaps; 3DDISTANCE gives exact 3D length to use in material ordering.

Alternatives to 3DDISTANCE

• DIST — measures planar distance (good for 2D or same‑Z points).
• MEASUREGEOM → Distance — a dialog-based measure tool that also supports snapping and incremental measurements.
• LIST — shows object properties (useful to see exact coordinates of vertices for lines/polylines).
• Properties palette — select an object (line, polyline segment) to see its length (but for lines only; not between arbitrary points).
• Use coordinate math: use ID command to get coordinates of points, then compute 3D distance with sqrt((DX)^2+(DY)^2+(DZ)^2).
• Use third-party scripts or LISP routines for batch measurements if you need many distances at once.

Why 3DDISTANCE might not work — causes and fixes

Problem: Command unrecognized or nothing happens when you type it.

• Fix: Check for typing errors; try 3DDIST or full 3DDISTANCE. If still not found, confirm your AutoCAD version and workspace. Reset command aliases by running the -TOOLSPACE or reinstall support files, or use the MEASUREGEOM alternative.

Problem: Results show unexpected zero or wrong DX/DY/DZ.

• Fix: Verify the UCS and whether points are being picked in the intended Coordinate system. If you’re working in a rotated UCS, switch to World UCS (type UCS → World) or specify world coordinates.

Problem: Picking points is imprecise.

• Fix: Enable OSNAP (F3) and set appropriate snaps (Endpoint, Intersection). Zoom in to the area and use object snaps tracking if available.

Problem: Measuring between non‑visible points (clipped view or different visual style).

• Fix: Adjust view or use PLAN/VIEW commands to ensure points are accessible; orbit the model so you can select the correct vertex.

Problem: Need repeated measurements or automated results.

• Fix: Use MEASUREGEOM for a dialog with multiple options, or a LISP script to automate repeated measurements.

Problem: Using AutoCAD LT or a restricted profile where the command behaves differently.

• Fix: Use the documented alternatives (MEASUREGEOM, DIST) or confirm features available in your product version.

Practical tips and best practices

• Always turn Object Snaps (OSNAP) on for precision.
• When copying coordinates into spreadsheets, use ID to list coordinates and paste them.
• If measuring between points on different UCS orientations, consider switching to World UCS to avoid confusion.
• For many measurements, script or LISP can save time (batch measurements).
• Use MEASUREGEOM when you prefer a dialog box interface or need to export results.
• Remember that dimensions (DIMLINEAR, DIMENSION) are meant for drawing annotation; 3DDISTANCE is for quick analysis/verification, not permanent annotative dimensions.

FAQ

What is the difference between 3DDISTANCE and DIST?

3DDISTANCE returns the true 3D distance plus DX, DY, DZ and angles. DIST is primarily for 2D plan distances (or distances on the current plane) and may not reflect vertical separation accurately.

Can I measure distance between two points on different UCSs?

Yes — but results depend on which UCS is active. For consistent world coordinates, switch to World UCS before measuring.

Why does 3DDISTANCE show a different distance than my dimension?

dimensioning tools may show projected (planar) lengths or be constrained by annotation placement. Use 3DDISTANCE for true spatial length; use a 3D dimension type if you need an annotative dimension representing spatial length.

How do I measure along a polyline (sum of segments) rather than straight line between endpoints?

Use MEASUREGEOM → Length for total polyline length, or use the LIST command on the polyline to get its length property.

Can I export 3DDISTANCE results to a table or file?

Not directly. Capture values manually, use the Measurement History if available, or run a LISP/script to collect and write values to a CSV or table.

What should I do if 3DDISTANCE command is missing or disabled?

Try the alternative commands (MEASUREGEOM, DIST), check your command aliases, reset AutoCAD support paths, or repair/reinstall AutoCAD. Also verify you’re using a product edition that supports the feature.

Does 3DDISTANCE work with object snaps on 3D solids and surfaces?

Yes — use endpoint, intersection, and nearest snaps on solid edges, mesh vertices, and surface edges to pick exact 3D points.

How can I get DX, DY, DZ if I only have coordinates?

Use the ID command for each point to get coordinates, then compute DX = X2−X1, DY = Y2−Y1, DZ = Z2−Z1, and the 3D distance as sqrt(DX^2 + DY^2 + DZ^2). Or use 3DDISTANCE to get those values automatically.