Convert DWG to SLDASM

Teams need this conversion when a DWG design must be edited, constrained, or checked as a mechanical assembly in SOLIDWORKS. Because SLDASM files reference separate part files, the process usually involves extracting or modeling components before creating the assembly.

What the DWG format is

DWG is the native drawing and model format associated with AutoCAD and compatible CAD systems such as DraftSight, BricsCAD, and ZWCAD. A DWG can contain 2D lines, arcs, dimensions, blocks, layers, external references, and, depending on the source, 3D faces, meshes, or ACIS solid bodies. It is common in architectural plans, manufacturing layouts, plant documentation, and AutoCAD-based mechanical designs.

A DWG is not necessarily a 3D model. Many files contain only drafting entities, so the file contents must be checked before selecting a conversion method.

What the SLDASM format is

SLDASM is the native assembly format used by SOLIDWORKS. It stores component instances, mates, configurations, display states, and assembly-level features, while the component geometry normally remains in referenced SLDPRT part files.

An assembly provides editable component placement, mating, interference checking, motion studies, bills of materials, and assembly drawings. It is suitable when the DWG represents several manufactured components, but not when it is only a 2D plan or a single undivided solid.

How to convert a 3D DWG

1. Open a copy of the DWG in AutoCAD, DraftSight, BricsCAD, or another compatible editor. Confirm that it contains 3D solid bodies rather than only lines, surfaces, or mesh objects.
2. Resolve or bind external references, remove construction geometry, separate unrelated components, and confirm the drawing units. Preserve the original DWG as an archive copy.
3. Export the solid geometry to a neutral CAD format. In AutoCAD, the ACISOUT command can write selected ACIS solids to a .sat file. If the source application can export an assembly-aware STEP file, use .step or .stp instead; STEP generally provides better cross-CAD exchange than SAT for multi-component models.
4. In SOLIDWORKS, use File → Open to import the SAT or STEP file. Set the correct units and import options. A single solid normally becomes an imported .sldprt; an assembly-aware STEP file may import with multiple components.
5. If the import produces one multibody part, use Insert → Features → Save Bodies or an equivalent multibody-part workflow to create separate .sldprt files where the design requires separate components.
6. Create an assembly with File → New → Assembly. Insert the part files, fix or ground the first component, and add mates that represent the intended mechanical relationships.
7. Save the result as assembly.sldasm. Keep the assembly and all referenced .sldprt files in a controlled project folder or manage them with SOLIDWORKS PDM.

How to convert a 2D DWG

Open the DWG in SOLIDWORKS with File → Open and use the DWG import options to bring selected views into sketches, or clean the file first in AutoCAD or another DWG editor. Delete duplicate entities, repair open profiles, remove unnecessary layers, and verify scale and units.

Use the imported sketches to model each component with features such as Features → Extruded Boss/Base and Features → Extruded Cut. The DWG does not specify all required 3D information: thicknesses, hidden geometry, manufacturing features, component boundaries, and mating intent may need to be supplied manually. Save each modeled component as an .sldprt, then place the parts in a new assembly and add mates.

Desktop and online conversion options

SOLIDWORKS is the most direct desktop option when the final deliverable must be a native, editable assembly. AutoCAD, DraftSight, BricsCAD, and ZWCAD can prepare the DWG and export SAT or STEP; dedicated translators such as CAD Exchanger Desktop can also convert supported DWG files to neutral CAD formats before import. Check the current format list and license capabilities because support for DWG, solids, assemblies, and native SLDASM output varies by product and edition.

CAD Exchanger Cloud is a reputable online option for converting supported CAD files to formats such as STEP or IGES, but it should be used only when its current format matrix lists the required DWG input and neutral output. Online services generally do not create a useful native SLDASM assembly with correctly separated parts and mates. Use an online converter as an intermediate-format service, then finish the assembly in SOLIDWORKS.

Do not upload confidential drawings until the service's retention, encryption, access, and deletion terms have been checked. For proprietary engineering data, use desktop software or an approved company-managed conversion service.

Quality and compatibility limits

• Renaming design.dwg to design.sldasm changes only the filename extension; it does not convert the internal data.
• DWG layers, blocks, dimensions, title blocks, annotations, and AutoCAD feature history do not become SOLIDWORKS mates or parametric assembly features. Keep the original DWG when drafting information must remain editable.
• SAT and STEP imports usually contain “dumb” geometry without the source feature history. Inspect units, origin, body count, face normals, tolerances, gaps, and design intent after import.
• Meshes and faceted surfaces are unsuitable for precise editable parts without repair or reverse engineering. STL is normally inappropriate as an intermediate format when dimensional CAD accuracy is required.
• A multibody import does not automatically define an assembly structure or mating scheme. Component separation and mate creation require design decisions.
• An SLDASM depends on its referenced part files. Moving or renaming those files can cause missing-component errors; use File → Pack and Go when transferring the complete assembly.