Module 02 / Assembly workbench
A 50,000-part assembly rebuilds in 1.4 seconds on a 32 GB desktop.
The Assembly workbench is large assembly CAD for mechanical teams who build machines, not toy fixtures. Seventeen mate types, a large-assembly mode that loads display data first and geometry on demand, and a published benchmark you can rerun on your own hardware. It ships in every Standard seat at $2,490 one-time.
02.1Benchmark
The reference file, on three machines you can buy today
REF-50K is a packaging line we modelled in-house for this purpose: 50,000 unique parts, 186,400 instances, 1.9 GB on disk as .swsx. The file and the timing script ship with the trial, so nobody has to take our word for it.
BENCH / REF-50K / 3 TIERS
| Measure | Entry · 16 GB | Desk · 32 GB | Workstation · 64 GB |
|---|---|---|---|
| Open, large-assembly mode | 38 s | 19 s | 14 s |
| Open, fully resolved | 4 min 12 s | 1 min 48 s | 1 min 21 s |
| Rebuild after top-level dimension change | 3.9 s | 1.4 s | 1.1 s |
| Peak memory, large-assembly mode | 6.8 GB | 7.1 GB | 7.2 GB |
| Peak memory, fully resolved | 15.1 GB* | 21.6 GB | 21.9 GB |
| Shaded orbit, frames per second | 11 | 38 | 60 |
| Full interference check | 9 min 05 s | 3 min 40 s | 2 min 20 s |
Entry: Core i5-13500, UHD 770 integrated. Desk: Core i7-13700, RTX A2000 12 GB. Workstation: Xeon W5-2455X, RTX A4000 16 GB.* paging to disk
Read the middle column first. That is the machine most of our customers already own, and it is where the 1.4-second rebuild comes from. The workstation buys you frame rate and a faster interference check. It does not buy you a much faster rebuild, because the constraint solve is single-threaded per subassembly and a Xeon is not quicker at that than a desktop i7.
The entry tier is honest about its limit. Fully resolved, REF-50K wants about 22 GB and the 16 GB machine pages to disk. In large-assembly mode the same machine opens it in 38 seconds and stays usable. If you buy hardware for this software, buy 32 GB of RAM before you buy a graphics card.
02.2Mates
Seventeen mate types, each with its degrees of freedom stated
The mate dialog shows the remaining degrees of freedom live, so an over-constrained subassembly turns red before you click OK rather than after a rebuild.
- CoincidentFace to face, edge to edge, point to plane. Flip and offset in one field.removes 1–3 DOF
- ConcentricCylinders, cones, circular edges. Optional rotation lock for fasteners.removes 4 DOF
- DistanceFixed value or min/max range for travel limits.removes 1 DOF
- AngleFixed or ranged, referenced to an axis you pick.removes 1 DOF
- ParallelPlanes, axes and linear edges.removes 2 DOF
- PerpendicularPlanes, axes and linear edges.removes 1–2 DOF
- TangentCylinder, sphere, cone or freeform face against plane or face.removes 1 DOF
- LockFreezes relative position. Use for welded or bonded pairs.removes 6 DOF
- SymmetricTwo entities about a plane. Jaws, clamps, guides.removes 1–3 DOF
- WidthCentres a tab between two faces, with optional clearance.removes 1–2 DOF
- SlotPin or axis constrained along a slot, free, centred or by percentage.removes 4 DOF
- HingeConcentric plus coincident in one mate, with angle limits.removes 5 DOF
- ScrewRotation coupled to translation by pitch in mm per revolution.motion coupling
- GearRatio between two rotating axes, by tooth count or value.motion coupling
- Rack and pinionRotation to linear travel, by pitch diameter or mm per turn.motion coupling
- CamFollower held tangent to a closed loop of cam faces.motion coupling
- PathPoint travels along a 3D sketch or edge chain, with pitch and yaw control.removes 2–5 DOF
02.3Large-assembly mode
Display data first, geometry when you touch it
Every .swsx part stores a tessellated display body next to its B-rep. Large-assembly mode reads only that display body, plus the mate references, until you select, measure or edit a component. Then it resolves that part and its direct neighbours. Nothing else.
The mode switches on by itself at 2,500 components. You can change the threshold per user or push it from the network licence server for a whole team. Subassemblies can be marked rigid, which skips their internal mate solve entirely. On REF-50K, marking the 140 purchased-part subassemblies rigid took the rebuild on the desk tier from 2.6 to 1.4 seconds. Most slow assemblies we are sent have exactly this problem: bought-in conveyors and motors carried as flexible subassemblies with 300 mates nobody will ever move.
What it will not do
Large-assembly mode does not simplify geometry for you. No defeaturing, no automatic envelope. If you want a 4,000-face motor reduced to a box, make that a configuration of the part. We tried automatic simplification in 2019 and pulled it because it changed mass properties without telling anyone.
Where the files live
Assemblies reference parts by relative path and by a 128-bit document ID, so a whole project folder can move between machines or onto an SMB share without broken links. For check-in and revision control the documented REST adapter talks to Git-LFS, PDM Works, Teamcenter 13 and SharePoint. We do not run a vault ourselves. Import arrives as STEP AP242 with product structure, Parasolid X_T or JT 10.5. The kernel and tolerance model behind all of this are on the product page.
02.4Price
Assembly is not an add-on
LIST PRICE / USD
- Standard perpetual seat, Assembly included
- $2,490
- Professional perpetual seat, adds Simulation
- $3,890
- Maintenance year, per seat
- $590
- Floating Standard, per concurrent seat, 5+
- $3,290
Every seat opens the same 50,000-part file. There is no part-count tier and no "large assembly pack" to buy later. A volume quote comes back from a person at the Austin office within one business day. Full terms are on Pricing
02.5From request to a seat
How a team moves its largest assembly across
- 01
Request the trial
Fill in the form on the contact page. A Windows installer link and a 30-day key arrive by email within one business day, with REF-50K and the timing script attached.
- 02
Run the benchmark on your machine
Twenty minutes. If your numbers sit far off the table above, send us the log. It is usually a GPU driver or antivirus scanning the project folder.
- 03
Import your own top assembly
Export it from your current CAD as STEP AP242. Product structure comes across intact; mates do not, from any vendor, so plan a day to re-mate the top two levels.
- 04
Buy perpetual seats or uninstall
Ask for a quote before day 30. The trial files stay readable in
sws-viewwhether you buy or not.
02.6Questions
What buyers switching from SolidWorks or Inventor ask
Not a fit if you lay out whole plants at 300,000 parts, or need a browser client. We say so up front.
Will my SolidWorks or Inventor assembly open?
Through STEP AP242 or Parasolid X_T, yes, as geometry with the product structure intact. Mates and feature history do not translate from any vendor, so you re-mate the top levels. As a SolidWorks alternative or Inventor alternative this is the real migration cost, and it is measured in days for most teams, not weeks.
What happens above 50,000 unique parts?
It opens, but we publish no figures past the reference file and do not sell on them. Above 50,000 the fit check on the home page sends you here for that reason.
Do I need a workstation graphics card?
No. The entry tier in the benchmark runs on integrated graphics. Viewport frame rate is what suffers, not correctness. Spend on RAM first.
Is there motion study or kinematics?
Drag-to-move with collision stop and mate-driven animation, yes. Forces, contact dynamics and motor sizing, no. That belongs in a dedicated multibody tool, and we would rather say that than ship a half version.
Next
Run REF-50K on your own desk this week.
Drawings from these assemblies, with balloons and BOMs, are covered on the Drawing page. Loads and fixtures on an assembly go to Simulation. Part-level features live on Part modelling.