(drafting) how do I dimension to a point on a spline?

[speedster29]

Hi,

I am new to NX5 drafting and I have come across a situation that I could do easily in another drafting program (cough, cough, IDEAS Drafting, cough, cough) but has me stumped. See that attached picture for a simple part I made to illustrate the problem. I want an overall length dimension on the part, but NX will not let me select the overall width of the part; it tries to snap to end or spline control points. Am I missing something?

 

[cowski]

There are a few options, however none are ideal. Check out this thread thread561-218499. If you do a search on the forum you might find a few more.

This is an area that I hope improvements are being made.

 

[hudson888]

speedster,

When you add dimensions there are different types of snap points that you could use but if you can't find the method that gives you the correct result than you may need to add a point to snap to and either blank it or move it to an invisible layer when you're done.

Cowski is correct dimensioning is really crying out for a point along curve method to allow that overall dimension to be more easily created.

Cheers

Hudson

 

[basenxuser]

Hi,

you can create a tangential line to the curve and use it as dimensional reference.

 

[speedster29]

I tried to create a tangential line and got unpredictable results. I ended up creating a small vertical line, aligning it by eye. It is close enough for a reference dimension.

 

[cowski]

When I need a line tangent to a spline, here is what I do: draw a line out in space parallel to the desired tangent line (for your example I would draw a vertical line). Next, using the inferred snap, pick near the point where the tangency will occur then pick the parallel line (not on a control point). A warning will come up saying the line could not be created, but it makes one anyway.

 

[speedster29]

Hmm, I found a problem. I was able to create a dimension, but the dimension scale was 1:1, not the view scale. In other words, if the actual dimension is 4" and the view scale is 1:2, the "faked" dimension shows as 2".

 

[ewh]

There are several ways to fudge this type of dimension. A somewhat accurate one is to simplify the spline, which will create lines and arcs (a lot of them). You should be able to create a tangent dimension, then hide that resuting geometry however you prefer.

Believe it if you need it or leave it if you dare. - [small]Robert Hunter[/small]