The only real limit is computing power.
We generate large assemblies (Bakeries ,food factories) In my experience you are better off braking the thing up into sections and only bring them together when each section is finished and it can be saved as a part this way you will be able to do without pulling all your hair out waiting for the thing to rebuild when you open it, best practice would be have a base sketch of the layout and mate parts to it to jog them around, if you need to edit any part derived from a assembly within the main model you can edit the assembly out side and replace the derived part with the new one.
in context only works for small stuff in reality, unless you can afford monster hardware.
Hope this helps.
As far as I know:
part = 1 cubic km centered on the origin
assembly = 10 cubic km centered on the origin
1 cubic km = 1 km cube
10 cubic km ≠ 10 km cube...
I stand corrected, Josh. I should have paid more attention in English class.
Ok, I beleive that I have found the answer.
Both Alin and Josh are half right.
I just finished making a solid part that was .5 Km long and then I added that part to a new assembly. Then I did an array, first small then big. The big size; which were end to end was 250Km long, made up of 500 .5Km parts. I didn't feel the need to use anymore time to see how big I could go. Now the software did show, but only for a short second or two a rebuild error but then went away as it did show the assembly at the correct length.
So sorry, Alin and Josh, but the latter part of your answer appears to be incorrect.
Just found this in the Knowledgebase:
The maximum size/modeller limit (model resolution space) has now been increased to 100 kilometers. The limit for all pre-2009 versions of SolidWorks is still 1 kilometer (1000 meters). Keep in mind that using such values in an assembly lowers the precision of the assembly.
All part size restrictions are still the same as in previous versions (1000 meters centered around the part origin, or 500 meters in a given direction).
I can just asume the they are talking about 100 km cube.