Expert: Bob - 6/12/2008

Question
QUESTION: dear paul,
Why regions extruded will take lot of bytes. Is there any way to reduce the size of file, first my 3d file was 2 mb,
when I added pattern with regions subtracted and extruded
the file size is 10 mb. Each operation became slow.
Is there any way alternative to reduce the file. I use
purging the file, but it do not reduce.

thanking you

mubin

ANSWER: Hi

I have a hard time to assist anyone who has not told me what I need to know to reply

-- your experience
-- the AutoCAD release
-- what you are trying to draw and why

If you are trying to draw a building in Acad 2002, that file size is not large.

If you are trying to draw a screwdriver in Acad 2009, that file size is ridiculous.

My guess is that you are on an old release and trying to teach yourself 3D --- perhaps trying to draw something that is better drawn in another program -- but it is only the best guess from what you tell me.

Write back with all details and I will try to assist you.

BOB

---------- FOLLOW-UP ----------

QUESTION: thank you,
I have dual 2 core new computer with 2 gb ram. I am using
autocad since 10 years mainly in 2d and sometimes in 3d.
my problem remains as follows:
 "think of some 100 holes in a rectangle, I subtracted these holes from the  rectangle , then I extruded the
resulting rectangle with 100 holes to say 100 cm.This is
my roof for a shade outside a building."
 I use autocad 2008. The problem is the drastic increase
in file size after using subtract boolean and extrude.

thanking you

Answer
OK --

Now I understand -- (but I am dear Bob, not dear Paul. lol)

Your computer is powerful enough - the graphics card affects the speed of getting your complicated project on the screen, especially with panning and zooming.

The basic problem is that you should be using AutoCAD Architecture or Revit to do an entire building. The Acad solids improved a lot for 2007, but they are nothing like the slabs or mass elements in ACA.
Autodesk may tell you that one can do an entire building in solids -- but the building needs to be simple for the file to be manageable. (a plain house, a plain tilt-slab warehouse, a simple office building)

The specific problem is NOT "Why regions extruded will take lot of bytes" -- the problem is the holes. Unfortunately, you did not tell me the shape of the holes-- square holes should require less information than fancy holes. If your hole has 8 surfaces, you have created 800 3D faces. (the size of each face is unlikely to add to the file size, it is the number of faces.  I am not clear whether a round hole counts as many small 3D faces -- probably it does.

One rectangular region extruded has the same number of faces as a cube -- do you see that? So the extrusion is only relevant to the file size due to the fact that it is complicated.

I am going by recollection on the issue of the 3D faces -- look it up.

If you are using the software for work -- I highly suggest you speak to your reseller, and change to ACA or Revit. Your time is worth money.

BOB