Projected views 1

[mielke]

In the US is it pretty standard to use the "third-angle procjection" style to represent a 2D view of a 3D object?

 

[trainguy]

I believe this is pretty standard all over North America (Canada and US)

tg

 

[mielke]

Thanks trainguy,

Also is there a standard way of showing dimensions in third angle projection? Should you or should you not double show the same dimension in different view points?

I know all of this is very dependent on the shape and complexity of the object. Im just trying to develop a standard operating procedure for CAD drawings that can be uniformally used over all drawings.

 

[cfee]

Yeah, 3rd angle projection is the right approach, and yes, you pick the best view of a feature to put its dimension, and don't repeat the dimension of that feature in other views, even if it appears there. Usually this is the view most closely related to the manufacturing step of that feature, but it should always be the view where the full contour of the feature appears.

If its a feature that only shows in its "normal" projection, consider an auxiliary projected view. But again, that's the only place the dimension for that feature should appear. However, all care should be taken to avoid dimensioning the feature to its hidden lines in the view where its obstructed by the rest of the part. Is this a hard and fast rule ? Well after referring to the ASME Y-14.5 dimensioning standard, you must decide.

I use the "Drawing Requirements Manual" by Global Industries as my go-to interpretation of the standard. It's around $200, but it quickly paid for iself in clarity and quality and consistency of delivered product, and our whole department uses it now. FAR cheaper than doing up a manual from scratch.

There- that's kind of the go in a nutshell. BTW- if a view is there and doesn't have a single dimension or note attached to it, strongly reconsider whether that view is remains in the drawing. Good luck and let us know how it goes !

 

[chicopee]

third angle projections are normally needed to reveal true length and tru area features which you would not be able to get with the traditional top,front, sides, bottom, rear views and one oblique views.

 

[rollupswx]

third angle projections are normally needed to reveal true length and tru area features which you would not be able to get with the traditional top,front, sides, bottom, rear views

Uhmmm, that is 3rd angle projection. You might want to check wikipedia on 3rd angle and 1st angle projection. Simply refers to the location of top, front and right side views.

 

[chicopee]

I must be in error then; for some reason I thought that third angle projections were oblique views.

 

[rollupswx]

http://en.wikipedia.org/wiki/Orthographic_projection