Sketches don't update properly ising design tables
Sketches don't update properly ising design tables
(OP)
I am using offset curves to create a revolved cut. The original curves are controlled by values in an Excel design table. For certain values the offset arcs are being created as compliments of the arcs that they should be.
Any ideas on how to constrain these to give me the geometry I want would be appreciated.
Thanks, Mike
Any ideas on how to constrain these to give me the geometry I want would be appreciated.
Thanks, Mike






RE: Sketches don't update properly ising design tables
Do you have a website that you could place your part in for download?
CorBlimeyLimey
Barrie, Ontario
FAQ559-863
RE: Sketches don't update properly ising design tables
What do you mean by compliments?
Are these conics (ie true circular arcs) or are they splines? Are you getting the "other half" of the arc? Are you getting to wrong side (direction) offset? DT's are Excel spreadsheets.
Are you getting some problems with angles going over 90, 180, 270, 360 degrees in your calcs? You can deal with this in Excel. BTW: not only can you put Excel cals, etc. in the DT parameter cells, but if you leave a blank row or column below or right of the "DT" cells, SW ignores the rest of the spreadsheet and you can do anything you want out there and link to parameter cells to the results.
I was - and he did. So at least I didn't get coal.....
OK, OK, It's a reference to my holiday sig. "Be naughty - Save Santa a trip..."
RE: Sketches don't update properly ising design tables
Is this a time depenpency issue? I've run into sutiations in the past where I've used a driven dimension to drive an equation (not recommended practice, but for the task at hand it was handy). It worked fine with the exception that I had to rebuild twice.
Like JNR, I don't know quite what you mean by "compliments of the arcs that they should be."
Hope it goes well...
RE: Sketches don't update properly ising design tables
http://www.amteam.com/Net_File011604.zip
I have 2 arcs that I using to make a revolve cut. The arcs are controlled by an Excel table to let me vary the radii. Typically the first arc will start at 0 degrees and go ccw thru 30 degrees. The second arc starts at 30 degrees and goes ccw thru 75 degrees. The 2 arcs are not tangent. These 2 arc are then offset and used for the revolve cut.
Sometimes the different table values work just fine and sometimes arc1 starts at 30 degrees and goes ccw thru 0 degrees and arc 2 starts at 75 and goes ccw thru 30 degrees.
If I trim this geometry then the configurations that were woking stop workiing.
Thanks, Mike
RE: Sketches don't update properly ising design tables
I was - and he did. So at least I didn't get coal.....
OK, OK, It's a reference to my holiday sig. "Be naughty - Save Santa a trip..."
RE: Sketches don't update properly ising design tables
Will try to be more precise when I get more time to look.
CorBlimeyLimey, Barrie, Ontario.
FAQ559-863
RE: Sketches don't update properly ising design tables
I was - and he did. So at least I didn't get coal.....
OK, OK, It's a reference to my holiday sig. "Be naughty - Save Santa a trip..."
RE: Sketches don't update properly ising design tables
Havn't forgotten you, just been too busy with work & Grandkids to spend too much time "researching".
Have you had any luck resolving the problem yet?
CorBlimeyLimey, Barrie, Ontario.
FAQ559-863
RE: Sketches don't update properly ising design tables
I strongly suspect that if your goemetry works manually and with certain values in the DT but fails with others, it is what I suggested - the smaller arc is getting bigger that the larger one before the larger one increases in size. So it "inverts" itself. If you change the order of the features in the tree and pay careful attention to this, you might fix it. On the other hand maybe not. You might have to do the DT value inputs it in steps so it never flips. You could put some Excel Bololeans in the DT cells to prevent the arc radii from over (or under) taking eachother, and force the use to enter the second value again after one arc has been updated. A bit cumbersome, but it might work.
Example: Imagine 2 concentric circles. Diameters are 0.5 and 1.0. If I increase the samll one to 0.75, it is still INSIDE the large one and I can increase the large one to anything I like of reduce it to a smig over 0.75. But if I increase the small one to, say 1.25 BEFORE I increase the large one to say 1.75, then it will not be INSIDE for some time during the update. Because it will be 0.25 larger than the large one for a short period of time. (same happens if I reduce the large one to less then 0.5 first.) Now in your case, you probably have some other sketch geometry which tied to your arcs and that's why it blows up with certain values, because it flips over and can't get back, because it finds a logicaL solution, but not the one you want.
Hope that made some kind of sense. It is hard to describe without your actual example to base it on.
I just though of something else. It definitely depends on what configuration you have active when you switch to the new one, so.....
If you have a dummy configuration in your DT which has the small arc VERY small and the large arc VERY large, then ALWAYS switch to that one BEFORE switching to a another one, it might solve your probelm becuase they could never flip.
Heck, I 'm just guessing in the dark here. But I have seen this sort of thing happen.
John Richards Sr. Mech. Engr.
Rockwell Collins Flight Dynamics
A hobbit's lifestyle sounds rather pleasant...... it's the hairy feet that turn me off.
RE: Sketches don't update properly ising design tables
Thanks, Mike