Just wondering -
If I have to choose between many relations or many dimensions, which (in general) is better (i.e. Faster)? Or is this one of those "its complicated" things.
I like to use relations if the dimensions may change, that way the other dimensions/features update using the relations. I think that really depends on a few things though and not sure there is a universal answer for that.
I almost always use relations instead of dimensions. I can't give you exact reasons other than the one Christopher Culver gave. For an example, I opened a file a while back that someone else had created. A hole was located in the center, but instead of using a relation it was restrained by a dimension of half the material width (not an Equation). When the material size changed during the design process of course the hole was no longer centered. If it had been constrained with a relation instead of a dimension that wouldn't have happened. Below is an illustration of how I'd have done it.
Before someone else says it, I know I could have done it without the construction line, but with the option indicated below turned on I'm pretty sure I can place the construction line, starting at the midpoint of the model edge, then drop the circle on it's end quicker than I could have just placed the circle and restrained it with dimensions and relations. This way all relations snapped in place while the sketch entities were placed so none needed to be added manually.
I'm a big fan of utilizing construction geometry, and I often use this method.
With that said, the more I can do with relations, the better - nothing worse than opening a sketch with a ton of dimensions an no discernible design intent!
I use more construction lines now than back in the last century on the drawing board.
Sure they are not needed, but makes Design Intent a lot easier to decipher when I open a design a year from now... ...or next week.
In general - relations over dimensions.
Marshall Wilson wrote: Just wondering - If I have to choose between many relations or many dimensions, which (in general) is better (i.e. Faster)? Or is this one of those "its complicated" things. Thanks! M
Marshall Wilson wrote:
I agree with Christopher Culver that there is no universal answer for that question but I think that the general consensus is relations before dimensions.
I started my answer, one of my guys came into my office with questions, I posted my answer and then see that Glenn Schroeder and Todd Blacksher have already chimed in.
I'm just not fast enough!
Absolutely i prefer relation B/C it be updated automatically when we change any thing .
Also i rarely use the blind in the extrude features (Cut & Boss ) and i use up to ...
I'll pile on - Relation > Dimensions almost all of the time. And don't hesitate to use construction lines, as Mr. Blacksher stated.
Thanks everybody for the thoughtful input! In general I'm a nut for relations because they are far more adaptible than simply dimensions. I asked the question because I'm putting together a model, and halfway through I found that I was just using lots of dimensions, even if there were a lot of equal sizes. I will probably go back and use equasions to tie them together as needed but in the back of my mind I wondered if there would be any performance gains to using a greater number of relations vs dimensions!
Thanks again for the input!
Like the consensus here I prefer a pure sketch solution (relations) whenever possible.
I asked the question because I'm putting together a model, and halfway through I found that I was just using lots of dimensions, even if there were a lot of equal sizes
For duplicate dimensions linking values is a viable alternative to equations/relations.
NIce thing about linking values is that it works across the entire model, not just one sketch. Even works for non-sketch dimensions.
One characteristic of Linked Dimensions I like is the ability to "buck" the Feature Tree Order. Here the Pattern Instance Count is used to calculate the spacing in a sketch higher up the tree. Also the extrude depth is fed back into the driving sketch.. pretty cool in my book
2016 Part & Video Attached
I’m never concerned with what’s faster. Do what’s best for the design.
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