Dimensions and sketches

[nick.kuzmik]

I've run into this problem a few times in the sketcher.

In today's case I draw a circle, then I draw a horizontal line through the center. Now I want to draw several lines at arbitrary angles to the first line. So I draw a second line and insert and angle dimension. I set that angle to whatever I feel like.

Then my horizontal reference line moves!

Where can I look up the "rules" for how Inventor decides which feature gets moved when I redimension a sketch?

[david.257019]

You need to use the constraints commands. Watch the tutorial on how these are applied and what they do. Don't forget you can also use the "?" help at any time.

I won't go into a blow by blow account of what each constraint does at this juncture, but to set you on your way - all you need to do to stop your base line moving is select the little "lock icon" from the constraint menu and click on your line. It will turn black indicating that is is now locked in place.

I don't know if you wish to use this base line for extrusion, but if not you can convert it to a construction line that takes no part in the extrusion process, yet stil acts as a construction reference.

To do this right click the line and go to the "Format" menu. In my Inventor 2011 at the top left of this menu is an icon which if you hover over it will tell you that this is for construction. Click the icon then right click anywhere on the screen and the job is done. Note that the line now appears as black dotted, signifying that it is both a construction line and locked.

I might have gone into more detail than you require, but I hope this helps.

Regards.

Dave