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geometry file size



Just out of curiosity: can someone explain the difference in file size between modfem and Parasolid x_t?

I have a CAD geometry, many complicated solids, I clean and rebuild this geometry then save the file.

The modfem is 180Mo, the x_t is 110Mo, there is nothing else in the file than the geometry.


It even looks like the modfem contains a copy of the x_t, in text format. So what is in the 70Mo of binary data? What explains the 63% in file size difference.


Or I guess my question might be: once you use FEMAP to clean/modify a CAD geometry, what is the best/lightest format to store this new CAD for later use in FEMAP?





Re: geometry file size

A follow up: originally I had a 99Mo stp file, containing ~10800 solids. In FEMAP I deleted a bunch of them and reduced this to 245 solids. And that's when I get a 110Mo x_t file...

I'm guessing stp format indicates operations and how the geometry is built, which means FEMAP has some work to do when opening it. If I export my 245 solid CAD as a stp, the file is 90 Mo...

Re: geometry file size

Whenever you have Parasolid geometry in FEMAP, it is not just the geometry that we are storing. For every Solid, Surface, Curve and Point there is additional non-Parasolid header data that is stored in the modfem. Things like the color, layer, solid title, meshing sizes and attributes... and most importantly the links to associate this information back to the Parasolid geometry. Much of this will still take up modfem space...even if you haven't explicitly assigned them.


If you want to see more about what is in your modfem, go to Custom Tools->Model Query->Model Contents. It should list some information regarding the actual type of data that is in the modfem. What is listed does not include the X_T data as you are correct, the modfem stores that intact in a separate section of the file.  If the listed information isn't clear, or provides some surprises, you can post it here and possibly I can provide some additional description.

Re: geometry file size

Great thanks George.

What is your take on which format is the best to store geometries for later use in FEMAP?

Note that I just need the "dead" geometry, no mesh sizes, associations...Etc... For ex its for making views as I write reports.

Accepted by topic author astrium_tls
‎11-22-2016 11:18 AM

Re: geometry file size

If all you need is the base Parasolid Geometry then I would just save all the geometry in FEMAP to a single X_T file. It is forward compatible to future versions and unlike an IGES or STEP there is no data conversion, so no chance of any issues of that type creeping into the process.


Of course, this only applies to Parasolid Geometry. If you have created any type of combined surfaces or curves, then you really do need to either save the modfem or a FEMAP neutral file.