Dimensioning 3D section views 1

[aafuni]

What is the proper way to dimension 3D section views. If you take a section as shown in the attached image, how do you properly dimension features on a diameter. Since your section will be looking at an angle to the top half (not normal) then dimensioning across is obviously not going to produce a diameter but a projected dimension.

I could just use radius dimensions to the centre line, and only on the bottom half of the view, but I was wondering the best accepted way to do this sort of view. I know others in the company have in the past just dimensioned across the part, then changed the dim values to represent the diameters, which is definitely not correct.

 

[PeterStock]

Use an aligned crossection. The upper portion would be rotated into the plane and the diameters look like diameters.

Peter Stockhausen
Senior Design Analyst (Checker)
Infotech Aerospace Services

http://www.infotechpr.net

 

[aafuni]

Thanks, I did not realize the aligned crossection was an accepted practice. It seemed odd to me as the view produced is not a true projection.

 

[PeterStock]

I would reject a section as you originally posted. An aligned section gives a true view of the hidden hole, the directly projected section does not.

Peter Stockhausen
Senior Design Analyst (Checker)
Infotech Aerospace Services

http://www.infotechpr.net