Hi Steve, I would not generally consider 3.6 MB to be a very big file. Maybe something like 15 years ago or so it might be more on the borderline of that possibly, but not these days.

I guess I would call that in a kind of "medium" sized range which I would put at a pretty broad range.

Are you having difficulties loading or dealing with the file?


It is likely that something around 95% of the data size of your file is contained in the surface data for the fillets. You can kind of get a picture of this if you select your object, run Edit/Separate on it to break it into individual surfaces, and then turn on control points with Edit/Show pts. You will likely see that the fillets are pretty dense with control points - that is a normal consequence of fillets as they have a curved shape to them and are not just simple flat surfaces. So it tends to take a fair number of control points for their shape to be described properly.


You asked:
> or would it be considered big in engineering circles?

Typically in engineering circles they are used to dealing with data of a size many times larger than that, so from that standpoint this would be small file definitely.


> I did an experiment: import stp to MoI, then immediately
> export. File size went from 471KB to 729B.

I'd consider that to be in the same ballpark, nothing particularly unusual or unexpected there...

If you would like to send me the files I could take a look at them and give you a more detailed technical explanation why the size grew a bit in that particular case. Were you exporting out as STP again?

It is likely to be something like MoI's STP export uses a larger number of digits in the point data that it writes out, like writing coordinates as numbers like -3.04520050437171 instead of truncating it to a smaller size like -3.0452

It is tough to say without examining your data but like I mentioned it is in the same ballpark and not at all an unusual or unexpected thing...

- Michael