Fun with feature statistics - patterns

For what it is worth-
Earlier this week we got a part from a client that took forever to
rebuild.
Looking at feature statistics (under the tools menu) we quickly
identified areas where we could astronomically speed up the rebuild
time. I highly recommend putting feature stats on a toolbar and using
it often - a case which I am about to attempt to justify
As delivered, this part had a 742 second rebuild time.
The most expensive features were a curve-driven pattern that took 557
seconds to rebuild, a fillet that took 85 s, and 75s, surprisingly, for
a 'simple extruded boss' that should not have taken any time at
all.
Turning off verification on rebuild (matt might want to pipe in here)
the rebuild time was reduced dramatically on the feature pattern to
just 28 seconds!!!,
Oddly, the fillet and the 'simple extruded boss' only lost a second
or two from their previous times (still over 2.5 minutes for the pair).
I should also warn that there is a risk associated with turning off
verification on rebuild because the geometry might not be any good and
you could add work to a fundamentally flawed model- to avoid this
without verification on rebuild, you have to manually check the model
with tools>check or a round trip Iges export/import, but for the
rebuild savings I have to admit it is justifiable on a part like this.
So, knowing all of that, how did we take this 742 second rebuild down
to under 36 seconds with verification on rebuild still on?
Where we got the biggest gains were by restructuring the part so we
could pattern bodies instead of patterning the features. As a body,
the pattern took just a little over 3 seconds, and combining the
patterned bodies took 26 seconds - all with verification-on-rebuild
active.
What is really interesting is that the 'simple extruded boss'
feature, which was not touched, went from 75 seconds to a tad over 1
second. The fillet was irrelevant - it was incorporated into the
patterned body instead of added after the pattern.
I just throw this experience out so you can keep it in the back of your
mind - if your instincts are that the part is taking waayyyyy too
long to build
a) use feature stats to see where you are blowing a ton of rebuild time
and look for anomalies (like that simple extruded boss). Old tip, but
always worth another mention
b) if a feature pattern is killing you, look for a way to combine the
features into a body that can be patterned and see if there is an
improvement. Even if the body pattern doesn't gain a lot, keep an
eye out for other features that benefit from the new structure (the
latter surprised the hell out of me)
Ed
Reply to
ed1701
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Incredibly useful topic, and definately new news to me.
Thanks - Bo
snipped-for-privacy@juno.com wrote:
Reply to
Bo
Ed,
This kind of thing was evident when we did the truncated icosahedron competition. There is no rhyme or reason to some of the things that we see. The fastest part was also the most complicated. Seemingly similar approaches had widely varying times.
snipped-for-privacy@juno.com wrote:
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