3DALIGN Command In AutoCAD : Aligns Objects With Other Objects In 2D And 3D

If you need a clear, step-by-step guide to using the 3DALIGN command in AutoCAD, this article explains what the command does, how it works, exact steps with tips for precision, common reasons it fails and fixes, useful alternative commands, and a practical FAQ for typical follow-up questions. Examples and best practices are included so beginners can align 3D objects reliably.

What is the 3DALIGN command?

The 3DALIGN command in AutoCAD is used to align objects in 3D space by matching three points on the object (source) to three target points (destination). The three point pairs define a transformation that can include translation, rotation, and optional uniform scaling, placing the selected object(s) onto the plane and orientation defined by the destination points.

Key uses:

Orienting a 3D model to match a survey or site geometry.
Placing components onto sloped or rotated planes.
Correcting orientation of parts imported from other coordinate systems.

How 3DALIGN works — core concepts

You select one or more objects to transform.
You then specify three source points on the selected object. These points define the original local coordinate frame (first two define an axis; third defines the plane).
You specify three corresponding destination points in the drawing that define the target orientation and location.
AutoCAD computes the transformation that maps the source point triangle to the destination triangle. You are then prompted whether to scale the objects based on the distances between point pairs.
If you choose Yes to scaling, AutoCAD applies a uniform scale so the distance between the first pair of points on the object matches the destination distance.

Important constraints:

The three points must not be collinear (they must define a plane).
The scale applied is uniform (not non-uniform/skewing).
Precision depends on accurate point picking — use Object Snaps (Osnap) and tracking.

Step-by-step: Using 3DALIGN in AutoCAD

Open your drawing and switch to a workspace that exposes 3D tools (e.g., 3D Basics or 3D Modeling).
Activate the command:
- Type 3DALIGN on the command line and press Enter, OR
- Find 3D Align on the ribbon: Home > Modify > 3D Align (location varies by workspace).
Select object(s) to align:
- Click the object(s) and press Enter.
Specify the first source point:
- Pick a precise point on the object (use Osnap like Endpoint, Midpoint, Center, or Intersection).
Specify the second source point:
- Choose another point that, together with the first, defines a direction on the object.
Specify the third source point:
- Pick a point not on the same line as the first two — this defines the plane.
Specify the corresponding first destination point:
- Pick the target location in the drawing.
Specify the second and third destination points:
- Select the two other target points that correspond to the source points.
When prompted “Scale objects based on alignment points? [Yes/No] :”, type Y for Yes if you want AutoCAD to scale the object(s) so the distance between the first pair of points matches, or N for No to only rotate/translate.
Review the result. Use UNDO (Ctrl+Z) if the result is incorrect and try again with different points or options.

Tips for precision in the process:

Turn on Object Snap (Osnap) and set commonly used snaps (Endpoint, Midpoint, Intersection).
Use Tracker and Temporary Tracking for accurate point picks.
Create temporary construction geometry (lines, points) as exact pick points if needed.
Work on a copy first: use the COPY command before 3DALIGN to avoid destructive changes.

Practical examples (short)

Aligning a door block to a sloped wall: pick two points along the door jamb base and a point on the jamb height as source, then corresponding points on the sloped wall plane as destination. Choose No to scaling to preserve door size.
Orienting an imported machine model to match site survey coordinates: use three distinct survey marks as destination points; choose Yes to scale if the imported model units differ.

Common reasons 3DALIGN doesn’t work and how to fix them

Problem: Points are collinear (on a single line) → Fix: Use three non-collinear points so a plane is defined.
Problem: Picked wrong points / low precision → Fix: Enable Osnap, zoom in, or create helper geometry for accurate picks.
Problem: Objects on locked or frozen layers → Fix: Unlock and thaw layers before aligning.
Problem: Working in the wrong UCS or a rotated coordinate system → Fix: Reset to World UCS (WCS) or set a proper UCS before aligning.
Problem: 3DALIGN command not available (e.g., using AutoCAD LT or older releases) → Fix: Use the ALIGN command (if available) or upgrade to a version with 3D commands.
Problem: Alignment distorted block or dynamic block → Fix: Explode the block or use a copy; some dynamic/block constraints can interfere.
Problem: Xref objects cannot be moved → Fix: Bind or detach the Xref or perform alignment in the source file.
Problem: Unexpected scaling / wrong scale applied → Fix: Choose No to scaling, or ensure the source/destination first-point distance is correct if you choose Yes.

Alternative commands and workflows

ALIGN — A general command that behaves similarly for many 2D and 3D cases. Use when 3DALIGN is unavailable.
UCS and PLAN — Set the User Coordinate System to a face or plane, then use simple 2D tools (MOVE/ROTATE) in that UCS to position objects.
ROTATE3D — Rotate objects about a specified axis in 3D; useful for angular adjustments.
MOVE / ROTATE / SCALE — Manual stepwise approach when simple transforms are needed.
Grip editing — Use grips to rotate/move objects interactively in 3D.
Align with reference geometry — Model small reference geometry (three points or a triangle) on the object, then use standard 2D ALIGN in the UCS of the target plane.

Choose the workflow that offers the right mix of precision and control for your task.

Tips and best practices

Always work on a copy when trying complex alignments.
Use three well-distributed points (not too close together) to reduce numerical error.
Keep Osnap and Ortho/Polar Tracking configured for the picks you intend to make.
If aligning to a plane face, use the face corners or dedicated vertex points rather than arbitrary points.
Check results with measure commands (DIST, LIST) and visual inspection in multiple views.
If your model uses different units, check and correct units before aligning or use the scale option deliberately.
For repetitive tasks, create scripts or custom macros that set UCS and run ALIGN/3DALIGN with predefined values.

FAQ — What’s the difference between 3DALIGN and the ALIGN command?

The ALIGN command performs similar tasks and is available in many AutoCAD versions. 3DALIGN is focused on 3D workflows and is provided in 3D-enabled AutoCAD workspaces. Behavior is similar: both map sets of points and can scale uniformly, but availability and UI placement differ by product/version.

FAQ — Can I use 3DALIGN to scale objects non-uniformly?

No. The scale option in 3DALIGN applies a uniform scale based on the distance between the first pair of points. For non-uniform scaling you must use separate SCALE operations or use more advanced modeling tools.

FAQ — What should I do if the command reports “points are collinear”?

Choose three non-collinear points that define a plane. Create temporary construction points if needed to ensure the three picks do not lie on the same line.

FAQ — Can 3DALIGN move or modify objects inside an Xref?

No. Xref geometry cannot be transformed by 3DALIGN in the host drawing. Either open the source drawing and align there or bind the Xref (make it editable) before aligning.

FAQ — Why did my object distort after 3DALIGN?

Distortion can result from applying scale when the source and destination point distances are disproportionate, or when the object is a dynamic/block with constraints. Try aligning a copy and select No for scaling, or explode the block before aligning.

FAQ — Is 3DALIGN available in AutoCAD LT?

AutoCAD LT has limited 3D capabilities. If 3DALIGN is not available, use ALIGN (if present) or perform manual transform steps (MOVE/ROTATE/SCALE) or upgrade to full AutoCAD for full 3D command support.

FAQ — How do I undo a 3DALIGN operation?

Use UNDO (Ctrl+Z) immediately after the command. If you saved, consider reloading from a previous version or use backups.

FAQ — How can I align an object to a curved surface?

3DALIGN requires three point pairs; you cannot map a single curved surface exactly. Choose three tangent/representative points on the curved surface to define an approximate planar orientation, or use more advanced surface-fitting tools in specialized software.