Let one dimension follows another dimension

Hi,
is it not possible, to let a distance always be 1/3 length of
another dimension ?

like here I need "B" to be 1/3 of "A" -I have a screenshot at:

http://putfile.com/pic.php?pic=9/27113302818.jpg&s=x4


SW 2001+

Thanks
Henrik

 

You could do this with sketch relations if you wanted. Draw a
centerline through the middle of the shape and divide it into three
segments. Constrain the three segments collinear and equal length, and
they can be used to divide into thirds.

Another more generic semi-graphical method would be to have a
construction line the same length as "A" and sharing one endpoint with
"A", at an angle where the cosine B/A. A line perpendicular to "A"
starting at the other end of the construction line will divide "A" by
the fraction B/A.

You could also use similar (same angles, different size legs) triangles.

 

Thanks for fast reply.
Henrik

 

I recently had a project where I needed to 'divide' a 90' long spline
into 30" sections. I was unable to do this in solidworks (I may have
missed a technique) but I remembered the good old divide command in
autocad, as much as I hated returning I have to admit that it worked
like a charm. Divide, select object, number of pieces to divide and it
places a point at the division location without destroying the original
line. Sometimes I wish solidworks had commands like this.

Zander

 

Once in a while I like to challenge myself to do things with as few
dimensions and equations as possible and rely on geometric constraints.

Here's a good challenge:
Bisect a randomly oriented line segment in a 3D sketch using only
sketch entities and geometric constraints. Last I checked, 3D sketch
had no midpoint or symmetry commands. It's tough, but possible.

 

Hi Jason,

How would you evenly space the ref points along a spline? As far as I
can tell only linear dimensions are allowed between them, when what is
needed is a 'spline length' dim similiar to an arc length dim where you
could select 2 points and the spline to set a distance along the curve.
I can't check right now but I'm sure I tried splitting and using equal
constraints, I don't think sw allows a 'equal length' constraint for
splines, although this is not feasible with over 30 sections.

Zander

 

SW 2005 can put datum points at even intervals along an edge. It
doesn't do any dividing or splitting for you, though.

 

You are a Genius!!

That exactly duplicates autocads divide command. I rarely use datum
point hence my absolute ignorance.

Thanks,

Zander

 

Insert Datum Points? In a Part or Drawing or Both?
I can Insert Points but don't see how to make even intervals.
Where is this???

 

Under reference geometry, points, apply to a sketch or body edge, then
pick # and spacing type.

 

thanks Zander... I can't believe I have overlooked that reference
Feature all this time!!!!

 

We laser etch many of our parts for stitch-weld layout. This will come
in handy for round and irregular edges