angle mates again.

Ha! I need an angle mate to be min. -1.5° (or 181.5) to max. 100 (or
80).

The funny thing is that when I cross that magical 0/180 barrier sw
automatically toggles the flip dimension value making it impossible to
set this (well maybe possible but apparently not by me). Maybe this
auto toggling is part of the problem with angle mates?

Zander

 

SW has had mate problems with 90, 180, 270 and 0 since day one. The
only reliable way to pass through is to get close and tip toe across.
The math to deal with this has been around for 143 years. It was
developed by a gentleman named Hamilton.

 

I'm guessing that Hamilton probably isn't working at Solidworks anymore
so I think there is definately a problem here! Of course, after
finding a working solution, next time I reopened the assembly the mate
values had flipped and my part was pointing 1.5° the other way.

Zander

 

Yes - this subject even came up on the NG a few days ago relating to
animator.

Last week I had to buy new prototypes (on our dime -company policy on
mistakes) because an angle mate spontaneously flipped and I didn't
catch it before release (no interferences in the assembly, just a part
subtly pointing the wrong way).

When I can, I try to 'coincident' mate component planes to sketch lines
instead (or better yet, 'coincident mates' to additional planes made
from those sketch lines so there is an explict choice on 'alignment').
I have no excuse for skipping that best practice last week. Stupid me.

Of course, that tip doesn't help with limit mates (which can be another
brand of ugly - lots of overdefinition for no good reason - I avoid
them and use configs, with a note for min/max in the dim itself
whenever I can). But in most cases mating to sketches or planes to
define the angle prevents avoidable and expensive problems.

Ed

However, as Paul pointed out, I am really tempted to point my finger at
them not paying attention to that mathmetician guy. Not my fault, not
my fault!

 

I know - that was me again with the animator thing... I'm having lots
of fun with limit mates lately.

Sorry to hear about the prototypes - it's one thing to make a mistake
and a whole other ballgame when the software decides to make subtle
changes for you.

My last prototype incident was simply having the rp place build the
'quote' file not the 'build' file..... that was their dime!

There are probably a dozen decent ways of emulating angle limit mates
but I still keep using them because either I'm lazy or too busy (it's
the later for sure...) - but seriously when they work they are very
usefull in my assemblies for testing trajectories.

Zander

 

I've never been able to count on angle or limit mates 100% of the time,
but I still use them because they make visualizing certain aspects of
the assembly much more straight forward. Here's one method that I know
makes them much more reliable. I agree, SW sucks at 0 & 180 degrees,
but now that you know that, you can simply avoid it (if possible).
Instead of having a range of -1.5 - 100 deg, create a reference plane
relative to your plane of interest that is offset by let's say 10 deg.
Now create your limit mate relative to the new plane with a range of
8.5 - 110 deg. The mate should function much more predictably now that
there is no zero crossing.

Also, on a side note, Limit mates and flexible sub-assemblies don't
often mix well. If you have only have 1 or 2 in your assembly it's not
a big deal, but any more than that and they will almost always mess up.
If you really need those 10 air cylinders to move realistically, just
make them from separate components assembled at the top level.

-Mahir