How To Define A Dimension

[Anonymous]

I know I should be able to figure this one out, especially after 20 days, but how do you define the dimension of a part? I can press/pull, but that only adds or subtracts. I want to click on two faces/edges, like the top and bottom of a cylinder, and define the length.

If anything the press/pull only adds to the confusion as my cylinder is 20mm, but when I select press/pull and click on a face it says 10mm, 10mm from where to where, the cylinder is 20mm not 10mm and it hasn't added anything yet?

[Anonymous]

btw I know I can go back in history and dimension the original extrusion, but sometimes I press/pull a face, and then I can't define the dimension unless I go into and change one of them while remembering what the other dimension is and adding or subtracting it. I'm looking for a way to constrain the dimension externally. 

[TrippyLighting · Accepted solution]

When you start creating geometry dont start with one of the primitives such as hte block, cylinder etc. Creat a Sketch, dimension the sketch ad then extrude ot push/pull it. THis will allow you to define dimensions. THis way of modelling is also refered to as parametric modeling.

the push/pull only modling is called DM or direct modeling.

[Anonymous]

Thanks, that's a little thing that makes a big difference. 

[burnandreturn]

In SpaceClaim there is the option to select where you want to measure your push/pull.  It is really fast to create geometry in this manner.   When you select the pull tool a small tool bar pops up and there is an option to select where you want to start the pull from.  So as in the OP's instance he would just select the bottom circuference and input the lenght he wants the cylinder to be.  That would allow one to stay in the direct modeling mode.   That  makes it very easy to modify solid models.   It would be a great addition if it was possible to do that in Fusion 360.

[burnandreturn]

Wow!  You guys at Fusion 360 are fast with implementing new features.   I went back in and tried the push/pull on a cylinder and all you have to do is click the face you want to pull and then click the bottom face.  The box pops up and the dimension is 0.00 and you just enter the overall length you want and presto.  Enter 20 and your cylinder is 20 mm tall.  Perfect!

[burnandreturn]

Now it doesn't work!   REALLY it worked but when I went back in it was doing really crazy things.  Disregard what I wrote in my last post.