CSYS by point, line, plane

[scotty7]

I've been playing with UDFs and would like to instantiate them with "on this plane, origin this point, horizontal vector this" kind of placement. I've tried to establish a CSYS to use as a base for the UDF using these inputs, and NX6 just isn't interested. I can do it as follows:
Create a sketch on a plane, and pick an entity for the HRef. Insert a vertical line, passing through the origin point I want to use. Now come out of the sketch, insert a Datum Axis through the sketched line, then through the HRef entity. Now define the CSYS on the resulting entities. It works, and the UDFs go in fine (need to include the sketch and the datums in the UDF too), but surely we should be able to define a CSYS directly from this type of input witout all the messing around.
Opinions?

 

[potrero]

Instead of sketching a vertical line, try simply selecting a plane perpendicular to that line.

For example, take a look at the Datum CSYS creation dialogue:

Insert > Datum/Point > Datum CSYS
change Type to X-Axis, Y-Axis, Origin
Choose your point for the Origin Point
Choose your line for the X-Axis
Choose your plane to pick the Y-Axis (NX will pick a vector normal to this plane)

Does this help you do what you want to?

 

[scotty7]

I can see where you are coming from, but I want the CSYS to lie on the datum plane I give it, whereas with your method, it lies on a plane parallel to the plane I give it that passes through the point. For example, I want to have the UDF lie on a particular face, but be centred about a point which lies off this face - the example that I was working was a crankshaft with the webs and journals being lined up but stacked upon each other.

 

[scotty7]

And lo, the option to do this has appeared in NX7.5

 

[sasha1]

Ive never been able to grasp where to use CYCS, I understand WCS and MCS but dont know where CYCS relates?

 

[JohnRBaker]

A CSYS is merely a 'saved' WCS. While you can only have a SINGLE WCS in your model, you can have several CSYS's located around your model which you can use for reference during the creation/editing of many objects. It also allows you to predefine origins and orientations of future WCS's so that if you wish to move the current 'Working' Coordinate System, you can go back and forth between these predefined 'locations' easily and repeatedly.

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA

http://www.siemens.com/plm

http://www.plmworld.org/museum/

To an Engineer, the glass is twice as big as it needs to be.

 

[potrero]

One area where NX CSYS's are invaluable is in complex machine design, where the CSYS's can be associatively placed (ie: location & rotation driven by variables) to represent important datum locations in the model. Each CSYS is a single "Feature" yet contains 3 datum planes, 3 axes, and a point, so the CSYS Feature is a very compact/lightweight (in the model tree) way to create needed datums.

 

[JohnRBaker]

Now are we talking about a 'CSYS' or a 'Datum CSYS', as these are two different objects? When you 'save' the WCS you get a 'CSYS'. In the case of a 'Datum CSYS', you have to explicitly create them, like any other feature.

That being said, a 'Datum CSYS', which is what you're talking about, can however be referenced as if it were a CSYS and it does have the added advantage of something which can be linked to other objects (as you mentioned) as well as having other objects linked to it. Try doing an Edit -> Move Object... using the 'CSYS to CSYS' Motion where the second CSYS is a Datum CSYS linked to some initial object. When you move the initial object, the Datum CSYS moves AS WELL AS the referenced object that you applied the 'associative' Move Object feature to.

As you go forward, just make sure that you understand which object type you're creating, being aware of what you can and cannot be done with each type.

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA

http://www.siemens.com/plm

http://www.plmworld.org/museum/

To an Engineer, the glass is twice as big as it needs to be.