true dimensions, do you use them?

i had another orthographic drawing view on a drawing that had this
setting changed to true dimensions. now of course this gave odd
results that we did not identify directly. and of course one of our
customers was designing to this information. bad news.

what i would like to know is if you use them how do you use them and
how are they interpeted. if i understand how others have used them, i
amy be able to apply this information in our designs if needed.

i have been doing mechanical engineering, PC board design, electrical
engineering, and a bunch more. i have never in my career had a need to
apply such a dimension in an orthographic or isometric detail view.
this is primarily due to the imterpertation of this dimension. my
opinion is that they should never happen on a detail drawing.

true dimensions are an out of the box concept, do not dis-own them
without understanding their purpose. right now i am sitting in a foot
thick lead sealed box. iQ

 

Using true dimensions in an axonometric projection would be acceptable
if the meaning were clear. I use it quite a bit from time to time.

The whole point of orthographic projection is to show the true lengths
of features by choosing views in which the projected length is the true
length.

Having the choice of true vs projected length add generality to the
software that when needed is needed badly. Like anything it can be
abused.

 

I use them when necessary, and that's when the best view is not one that is
normal to the surface or points I need to dimension. If you put dims in an
iso view and they are projected, that's what you get - the distance that is
how far it is between those 2 points as they project to your viewing plane.
But if you really want the true dimension between those points, then tell it
to use true dimensions and you will get the actual distance.

WT

 

FYI,
I think this error occurs when you insert an ISO view and then later
change that view to some orthographic view.

When you insert the ISO view, the view defaults to display TRUE dims.
When you change the view to an orthographic, the dim type is still TRUE,
causing some confusion.

If you insert an orthographic view in the first place, the dim type
defaults to projection.

 

I would have to try it to be sure, but I think that the existing dims are
deleted when changing into iso view.

WT

 

Yes, the existing dims are deleted, but the default dim type is what I
am talking about.