Heavy file slows down and force closes AutoCAD

[bruno.ruas]

I'm an architecture student working with AutoCAD 2012 to model a complex 3D figure of a project for one of my subjects. The project involves mainly several metallic truces, which I modeled like this:

==> After making some guide lines for the dome which the truces would be part of, I used "loft" to model the bottom half of the dome, and the "patch" command with two guide lines to close the top

==> Then made several planesurfaces, which I used the "Intersept" command for along with the dome surface, that way I got the guidelines for the truces

==> Finally used the "sweep" command in all of the truce guidelines to model the cilindrical truces

However the large amount of truces makes it hard for the laptop to proccess properly. Currently the 3D file reduced to it's most simple form is over 40Mb large. My idea is to be able to export the model to an .stl file (litography) so that I can use it on a 3D printer for a plastic scale model, but because of how large and complex the model in the file is, AutoCAD eventually freezes and force closes.

What can I do about this? How can I make it possible to export an .stl file without risking another force close? I don't really think that it's of any use to work on other computers at the university since my laptop has better specs than all of them.

Here's a short list of my laptop's specs so that you have an idea of what I use to work.

Operating System
MS Windows 7 Home Premium 64-bit SP1

CPU
Intel Core i7 2720QM @ 2.20GHz 53 °C
Sandy Bridge 32nm Technology

RAM
8,00 GB Dual-Channel DDR3 @ 665MHz (9-9-9-24)

Motherboard
ASUSTeK Computer Inc. N55SF (CPU 1) 52 °C

Graphics
Generic PnP Monitor (1920x1080@60Hz)
Intel(R) HD Graphics 3000
NVIDIA GeForce GT 555M

Hard Drives
625GB Hitachi Hitachi HTS547564A9E384 (SATA) 33 °C

Optical Drives
Slimtype DVD A DS8A5SH

Audio
Realtek High Definition Audio

I'll be waiting for an answer in the mean time... and trying to keep my cool and patience so I don't use a sledgehammer on my most needed working tool... Thank you everyone.

[Kent1Cooper]

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@bruno.ruas wrote:

I'm...working with AutoCAD 2012 to model a complex 3D figure.... The project involves mainly several metallic truces...:

==> After making some guide lines for the dome which the truces would be part of.... 

....the large amount of truces makes it hard for the laptop to proccess properly. Currently the 3D file reduced to it's most simple form is over 40Mb large. ....

....How can I make it possible to export an .stl file...?

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[I will assume that the word you mean is "trusses."]  If the dome is a regular dome shape [surface of rotation], and the trusses are identical, have you tried making just one truss, defining that as a Block, and making a polar Array of such Blocks to form the dome structure?  A Block insertion takes a tiny amount of memory, no matter how memory-intensive the Block is.  If the truss definition that is complex is only in memory once, with its repetition left to Block insertions, it would greatly reduce the AutoCAD .DWG file size [though it might not reduce the amount of work required to render it, or perhaps to make an .STL file from it].