HUGE File Export Problem in V9

I imported an AutoCAD DWG 2000 file, made no changes and saved it as a SKF.
I immediately saved it as a DWG and the file size grew from 1.7MB to 74.3MB.
If I saved the SKF file to a DXF it grew to 400MB!!!

Any ideas?

 

Are there a lot of curves in the drawing? A lot of layers? Symbols? Text? Fills?

Curves may be exploded into multi-faceted polygons - from 2 'nodes' defining the start and end points of the curve, you may go to 20 points describing the same curve.
(You may also find that sometimes converting filters are confused by curves and they are drawn twice - on top of each other.)

Layers are handled differently in different programs; Each layer may act as a separate file with duplicate information on each layer; the program combining them into the one drawing.

I don't know how ACAD handles symbols, but it may be that a symbol in ACAD is only a pointer to a group of lines, and the other file formats have to explode this group and duplicate it every time the symbol is reproduced.

Text may be converted to outline shapes when changing file formats - instead of an "A" taking up one slot of space, each point within the shape now takes up a slot; 12 spaces - even worse for letters with curves in them.

Some fills have to be converted to lines, or individual bitmaps for each area filled. Solid fills may also be replaced with solid hatching; this will bloat the file.


An easy way to see how much repetition and 'dead' space there is in a saved file is to zip it: Zip works (roughly) by replacing repeat areas of code (like spaces) with "this is repeated x times". A program may save a file where everything is separated and in the right place so the drawing is quick to draw/edit while working on it; some file formats do this more efficiently and with more consideration of file-size than others.

Hope this helps in some way

Gadget