Referencing .STEP file as Basic Geometry

[MikeRzMachine]

Hello,

I have searched in the Y14.5-2009 standard and online and have not been able to find an answer to this question. Is there a way to reference a step file as basic geometry to apply a profile of a surface tolerance?

The main purpose is to define a tolerance zone for surfaces with compound curves and other shapes which are not straightforward to dimension. I would expect that these parts would be inspected with a cmm, but could also be inspected (very tediously) using manual means. I would use datums to orient the step file geometry.

All of my searches point me to adding GD&T callouts to step files, which is not what I'm trying to do.

Is there an accepted means for referencing step files through gd&t?

Thanks,
Mike

[Belanger]

Check out paragraph 8.2 of the Y14.5 standard. In the middle it says that "a digital data file or an appropriate view on a drawing shall define the true profile." Most of us are used to having the true profile be displayed/dimensioned on the view itself, but it does allow for a digital file.
They don't say exactly how to communicate such a thing, but I imagine it would be via a note referencing the CAD file or whatever.

Maybe I'm just rehashing the other stuff you saw; you can follow-up with more questions if I'm off-base..

[Kelly_Bramble]

Typical notes on an engineering drawing referencing the 3D/2D cad Model.

1. Use 3D CAD Model as Control Master for Shape Reference.
2. This is a Limited Dimension Drawing, Unless Otherwise Specified, Feature Geometries Are Governed By The Electronic Database. Tolerance of Electronics Data Base Features Shall be +/- .XXX.
3. Untoleranced Features are Defined in the Digital Database CAD File # XXXXXX