Currently using NX 188.8.131.52...question about pattern feature, simple vs variational
I have a couple of patterns in a new seed model I am creating. One is a circular pattern of a rectangular pocket. I noticed that every time I update my model to test it, I get new expressions. I am up to p50000...and with every subsequent update the lagtime increases. I'm getting Y2K flashbacks
I have been looking around for solutions and noticed I should be using simple. I looked and mine is created as a variational. I tried to edit it to simple but it bombed and said unable to perform boolean...
Shouldn't that be an easy edit? There is nothing attached to this pattern, no blends, nothing. It is basically just a cylinder with a pocket on the end instanced around...
Or, is there a preference I can set to not have a separate expression bundle for each pocket?
Or should I start over and make it a simple pattern...
Solved! Go to Solution.
Without having the part to examine, it's difficulat to say exactly what the issue might be.
I created a simple part in native that shows what is happening. I attached it. During that I discovered what set it off. As soon as I set the pocket size and pattern quantity to another expression, I got the extra expressions.
I initially made it a variational just like my original model, so it may be that? But, I tried to edit it to simple and no go. I put another pocket on the other end of the cylinder and tried to make a simple pattern of that and it wouldn't do it? Maybe I am doing something wrong here...
This is how my other model started, and it made more new expressions every time I 'flexed' it and it got slower and slower...
While I can't see exactly why this is happening, I did go and check this using NX 9.0 and it appears that whatever the issue was, it has been fixed as the number of expressions do not change when edited (note that I verified that this was actually happening in NX 8.5 and used that same exact workflow in NX 9.0 as I did in NX 8.5).
However, there is something that you can do in NX 8.5 that might work much better in the end. Rather than using the Pattern Feature function, after creating your initial pocket, use the 'Pattern Face' function found in the suite of Synchronous Modeling functions instead. This give you a much simpler model with almost no additional expressions.
Note that in NX 9.0, we've enhanced the 'Pattern Face' function so it now has the same capabilities as the 'Patter Feature' function so for something like this, you may wish to consider using 'Pattern Face' in the future, or at least giving it a try before you use 'Pattern Feature'.
Thanks John, I changed my model to use pattern face instead and that looks good, kudos to you sir!
Is there a reason why simple pattern would not work for that pocket?
From what I've experienced since Pattern Feature was introduced it seems to be the edge blends that change is the root of the issue. I think they've done some work recently to minimize that limitation but it's still something that will be an issue to some extent.