Drafting: Datum on a curved surface
Drafting: Datum on a curved surface
(OP)
I am wondering if there is a way to hang a datum off of a curved surface. See attached picture which shows what I want to do. I was able to accomplish the view in the picture by going into active sketch view, zooming in on the tangent point of the curve and putting in a tiny line that I could then hook the datum to. I'd prefer to be able to put it on the part itself so that it is associative if this is possible?
NX 8.0/TC8





RE: Drafting: Datum on a curved surface
Tim Flater
NX Designer
NX 8.0.3.4
Win7 Pro x64 SP1
Intel Xeon 2.53 GHz 6GB RAM
NVIDIA Quadro 4000 2GB
RE: Drafting: Datum on a curved surface
Are you getting at hanging the datum off the extension line of the dimension? That kind of works, but I am unable to slide the datum down below the arrows of the dimension. I can slide it up along the extension line, but it needs to be down below all the dimensions.
NX 8.0/TC8
RE: Drafting: Datum on a curved surface
How about a leader with no text (or a [space]) with the datum coming off the stub, like a Radius dimension would have the datum on the stub?
If the suface is a true arc, you should be able to attach the datum flag to the arc. If not, then ignore this suggestion.
You can set the Type to Flag in the Datum Feature and pull that off of an extension line, but that's not what you're showing in your image.
In a manner of speaking, your initial method (as a sketch in drafting) should be associative, if you've geometrically constrained the line to the arc/surface properly. If the arc/surface moves, then so should the line, unless you completely delete the surface/face.
Tim Flater
NX Designer
NX 8.0.3.4
Win7 Pro x64 SP1
Intel Xeon 2.53 GHz 6GB RAM
NVIDIA Quadro 4000 2GB
RE: Drafting: Datum on a curved surface
RE: Drafting: Datum on a curved surface
RE: Drafting: Datum on a curved surface
RE: Drafting: Datum on a curved surface
RE: Drafting: Datum on a curved surface
I attached another example that has the same issue, but perhaps is a bit more of a common scenerio and I don't think anyone can debate the legality of it! It is just a simple extruded circle and I am calling one of the flat surfaces datum A. Since it is a circle, and in the right side view the edge is actually an arc, I cannot grab it to drag my datum down as shown. If it were an extruded rectangle, I would be able to grab that edge. The way I was able to create the datum A shown in this case was to put in a dimension across the width of the part, turn off all the arrows, the text and the left extnesion line, then hook the datum A to the right extension line. This just seems like a painful process to go through to get the desired result so I'm wondering if there is an easier way other than this?
Also, before anyone tries to tell me I can just hook the datum onto the face of the part, I'm aware that is a legal way to represent the datum, but as I'm sure many of you can relate to, there are many people at my work that have seen it done the way shown in the picture for 30+ years and refuse to change their ways.
NX 8.0/TC8
RE: Drafting: Datum on a curved surface
What I do is attach the datum to a dimension extention line.
RE: Drafting: Datum on a curved surface
1. right click on the view and select Activate Sketch View
2. draw a line from the appropriate end point (selection scope must not be set to Within Active Sketch Only)
3. finish the sketch
4. place the Datum on this line
With this method, it is much easier then placing the dimension first and then hiding all the geometry, that must not be shown.
Hope this helps in reducing the steps for placing the Datum.
RE: Drafting: Datum on a curved surface
Just place the dimension and attach the datum to the extention line from that dimension.
RE: Drafting: Datum on a curved surface
You will run into trouble if you are not
RE: Drafting: Datum on a curved surface
I believe the OP was stating that the method he used in the second attachment involved hiding the dims - just as a way of letting us know the route he took for that datum feature appearance. Sven was just pointing out that adding a sketch or view dependent curve was probably eaier than going through the OP's hiding method.
I agree with you in that Datum Feature extension lines need to be addressed for a few things, especially the side view of a cylinder or curved shape like the OP has.
Tim Flater
NX Designer
NX 8.0.3.4
Win7 Pro x64 SP1
Intel Xeon 2.53 GHz 6GB RAM
NVIDIA Quadro 4000 2GB