I'm making an inseparable assembly. Holes are being added at the assembly level. However, the datum hole keeps changing it's measuring location when I switch configurations (see attached pics). The pics show config 1 where the holes should be. When I correct the location of the holes in config 2, config 1 goes haywire in the opposite direction that 2 did originally. I tried making these with the Hole Wizard, then with the cut feature and it happens both ways. Any ideas on why this is happening?
Hi Raymond
I'm not entirely sure I understand your problem. Is it that the dimensions are flipping direction in one config to the other (and this doesn't always happen)?
If it's what I think it is.. You must use an offset dimension to stop this from happening.
This offset dimension can be created from offsetting a plane or a line.
As far as I know, this is the only way to avoid these kind of dimension flipping issues.
The reason is simple an offset dimension contains a direction. Normal dimensions do not.
Is this really the case Rob? Is this the case for all Offsets; Dimensions, mates, planes etc.? Can SolidWorks really be that instable? Genuinely intrigued as I've seen some strange Flips in certain parts throughout the years...
Hi Mark
Maybe things have improved, but I used to be plagued with flips where Solidworks finds the closest solution, even if it means reversing the direction.
Using Offsets eliminates this condition. It's worth keeping in your back pocket if you have a situation that is causing you troubles.
Yeh I used to have the issue as well but I couldn't tell you if it was something SolidWorks was doing or if it was me not securing everything down properly. Worst offender was Angle mates if I remember, to the Point I don't use nor trust them anymore.
Right after I made the post it hit me what the problem was. There's three configurations for this assembly total. The main config has an outer parent shell that is suppressed in the other two configs. In the other configs, the internal frame was fixed. It must've moved from the original location somehow before it was fixed, which was throwing everything off. I just opened the main config, deleted the shell placement mates and mated the frame to the planes in all configs. Fixed everything.
Hello,
I'm not seeing any dimension "flipping" or wired hay.
In image 1, the vertical dim isn't shown, but it is in #2.
The hyper-precise locating dims appear to go to a floating point as the baseline anchor.
When the config changes, it appears the vertical dim gets bigger (or the vertical assy height shrinks or the vertical dim's upper anchor shifts) and the unanchored (assumed) point is moved off the assembly.
Why it moves to the right as well, I can't speculate, but as Mr. Edwards suggested, I believe you have to better anchor you locating dims.
Also evaluate if the vertical dim is maintaining its upper anchor and whether it's value is correct, but the computation results in the hole being put into space.
Kevin
The locating point is on the frame behind the plate you're seeing. The 6.283 (6.326 in my pic below, which I changed just now on purpose...don't psychoanalyze why they're different) is for another hole which is why I didn't care to capture it. This picture should clear up where the datum is. Also, my response prior to yours may help clear up what was happening.
My first question would be what are you placing dimensions from to locate the holes?