Autodesk Inventor

[#1]

I have a question about horizontal and vertical constraints using Inventor 2012 Pro. When I start a sketch in the front view ( XY) plane, I normally constrain my sketch to be center around the origin by using the horizonal and vertical constraints.

Example, a rectangle, midpoint of a side contrained to the origin using horizontal contraint, and then top or bottom midpoint contrained to origin using vertical contraint. Sometimes I create a part on the side view (YZ) plane and these contraints are reversed. To constrain the side midpoint of the recantagle I need to use vertical constraint instead and horizontal and vice verse for the top or bottom midpoint contraint to origin.

Not really a deal breaker, but I find my self pressing the undo button quite often as I model new parts, not really thinking about what plane I am sketching on. Is there any options I can select or apply to resolve this?

I think I know why it does this, becasue in the XY plane, Y is vertical, and you would think that when sketching the same part from the YZ plane, Y would remain in the vertical but it seems to switch, Y becomes horizontal and Z becomes vertical?

Thanks

Sean

[#2]

Hi

I can't explain why it happens, hopefully someone will shed some light on the subject.

To help you immediate problem:

Have you enabled "Look at sketch plane on sketch creation" ?

If not, this will orientate your sketch correctly, it might lie on it's side, but at least you know which constraint to use.

"Application options, Sketch tab"

Hope this helps.

[#3 · Accepted solution]

I'd strongly recommend constraining rectangles by using a diagonal construction line constrained at the midpoint.  Inventor 2013 includes a tool to do exactly that, but Brian Hall wrote an add-in that many people have been using for a number of years to do this.  It's posted in mCAD Forums here.

The advantages of this method are: the constraint is more visually obvious; corner fillets & chamfers don't affect the center constraint; it's quicker if you use Brian's rectangle tools.

I agree, though, that the definition of horizontal and vertical are not always clear.  Even if you work out the logic for the origin planes, sketches created on part faces, work planes, etc. are always a guess.  I suppose the obvious answer is to display the sketch coordinate system indicator (App Options > Sketch tab), so you always know which end is up.

[#4]

I have installed the add-on, very useful tool.

I have a question though, when constraining the midpoint of the diagonal line in a rectangle to the origin, inventor says that the sketch is fully constrained, but can't the sketch rotate on that midpoint? 

What I view in my head, example; I have a rectangle sitting on my desk, I use one index finger to hold down midpoint of a side to the x axis, then i use my other index finger to hold down the top or bottom midpoint to the y axis, this rectangle can never move if because of the placements of my fingers holding down in those specific spots.

But if that same rectangle had a diagonal line  from corner to corner and I use one index finger to hold it's midpoint to the origin, theoretically I can rotate the rectangle on that constraint.

Am I supposed to be applying another constraint to prevent this rotation?

[#5]

It automatically applies a horizontal or vertical constraint to one of the sides (plus the usual perpendicular and parallel constraints to the others).

[#6]

Ok, Thanks!