Relate one dimension to another during model sketching

Inventor user here.

I want to center a rectangle on the origin. so I want one side of the
rectangle to be L and the distance from the origin to be L/2. So that if I
change the width of the block by delta L, the block grows in both directions
by delta L / 2.

With Inventor when I create the L dimension, then when I add the "L/2"
dimension from the origin to a side, I simply pick on the L dimension and
then type /2

I know this is basic, but what's the analogous workflow here? btw SW 2003.

Additionally, I can display a dimension as a formula in Inventor, i.e.
"d2=1.5". How do I do that here?

 

jiml,

Instead of using /2 dimensions to make the rectangle central, why not use
sketch geometry. What I do is:
1. Draw a rectangle
2. Then draw a construction line from one corner, diagonally to the opposite
corner
3. Add a relation between the origin and the midpoint of this construction
line
4. Now add overall rectangle dimensions only (length & width)

The rectangle will be fully defined and central with just these 2
dimensions. When you change one of the dimensions, it will stay central.

I have a simple macro that I recorded years ago (that I use all the time to
this day), that will create this sketch for me automatically. All I have to
do is add dimensions. If you want it, let me know and I will send it to
you.

 

Thanks Seth,

I stumbled across this very technique in my "Engineering Design with
Solidworks 2003" book. Thanks! I doubt if I'll be using SW after this little
job. Thanks anyhow for the offer!

Still curious how you relate 2 dims to eachother . . .


Jim

 

Jim,

If the relationship is a formula (dim1=dim2*.5), you can use equations.

If they're the same, you can use "link values".

Regards

Mark

 

We have two part templates that go a step further - one a rectangular part,
the other a circular part. Both then are extruded as midplane so now the
part is totally centered on the system planes. Just change the dims and
away you go.

WT