Trouble with Model > Sketch > Rectangular Pattern

[garylwenger]

I've been working on a sketch that requires the use of the Rectangular Pattern command, and am not understanding why the command is leaving me with many multiples on top of each other. So I began a new design using the command to try to get to the bottom of the problem. I drew a box with filleted corners -- eight sketch entities in total. But when I window-select them for patterning, the dialog box shows twenty selected! If I pre-select the entities one at a time, which the command allows, it shows only the eight that actually exist -- the right number. Any idea why this is happening?

BTW: I saw one of your folks suggest to another forum poster (on a different matter, the mirror command) that it is better to pattern bodies than do the patterning in the sketch. I guess I'll be doing that in the future.

[jeff_strater]

yes, in general, it is probably better to use feature pattern, if what you patterning is solid geometry.  There are times when I use sketch pattern, but it's pretty rare.  Feature pattern is more efficient for large patterns.

I'm not sure about how you ended up with multiple copies of the geometry on top of each other.  That should not happen with sketch pattern.  Can you show a screencast of your workflow to help us understand how that might have happened?  I know that this can happen if you use Copy/Paste of your geometry, and if you do undo.  But, I'm not aware of other cases, especially with sketch pattern.  Anything you can do to enlighten us will be helpful

Jeff

[garylwenger]

Hi Jeff. Thanks for the timely response. I've included a Screencast showing my sequence of moves (I hope you can view it; it's my first time using Screencast). Note that no Copy/Paste was used nor any Undo's invoked.

You will see that after I window-select the 8 entities I wish to pattern, the Objects field in the Rectangular Pattern dialog box shows 28.  

And thanks again

Gary

[jeff_strater]

Thanks for the screencast.  This is normal.  I think I can explain what the 28 entities are.  You have:

• the 4 original lines from the rectangle
• the 2 construction lines (the dashed lines)
• the 4 endpoints of the construction lines
• the 4 fillet arcs
• each fillet arc has 3 points (two endpoints, one center point), for a total of 12
• there is a point at the center of the construction lines
• there is another point at the sketch origin

So, there should be no problem.

Jeff

[garylwenger]

That explains it. It did occur to me that it may have been counting some of those things but when I saw 28 under Objects, I wrongly assumed that that was too many for what was there -- should have counted them myself. Still, to my way of thinking, for the purposes of patterning in a Sketch, you just want to duplicate the actual entities (the construction graphics could be left with the original). And you certainly don't want to have to individually pick everything, especially, if what you're patterning has many entities.

In any case this is probably moot, considering that I successfully patterned my "seed" feature using Create > Pattern and Create > Mirror. In other words, your advice worked, and without the slowdown and crashes.

Thanks Jeff

Gary

[garylwenger]

I forgot to mention that the multiple copies were almost certainly the result of my first, rather struggling experience with that command; took me a while to understand how it worked.

Gary

[jeff_strater · Accepted solution]

Hi @garylwenger, you are correct.  You do not need to select all 28 of those to do the pattern.  In your case, you can just select the 8 items (4 lines, 4 arcs) that you want to pattern, and it will work fine.  Fusion will automatically add the necessary points in, and you don't need the construction lines in the copies.  However, all the sketch objects are selectable, so if you window select, you get everything that could possibly be selected.  We try to make it as tolerant as we can of different selections, and just add what we need or filter out what we don't need.

Jeff

[garylwenger]

Yes, I see. Thanks for the help, Jeff.

gary