- Can we dimension a line location from an axis or plane? (i am unable to select axis)
- In sketch mode, can we create offset sketch from a feature?
1. If you want to sketch from a line or plane, you need to use the project geometry command. You use the command, then select the axis and it will put a point in your sketch to reference it. You cannot select entire work planes though. You can however, select the face of existing solids or lines and points from other sketches into the new sketch.
2. Yes you can. The easiest way to do that is use the plane command and then begin to drag the plane in the direction you wish to offset it. Then once you have it moving in that direction type the distance you want it to be offset. once you've done that, start a sketch on the plane and just use the project geometry command by selecting whichever features you need for sketching on the new plane from the solid shape or sketch you created before.
A tip for you to make life easier down the line with designs. ALWAYS and ALWAYS and ALWAYS make sure your sketches are fully constrained! Inventor will tell you in the bottom right corner of the screen in sketch mode if you still need dimensions/constraints or the sketch is fully constrained when you are finished. Not having a constrained sketch will save you a ton of pain and annoyances down the road in the design. All it takes is one little mistake in a sketch to mess up everything.
Another tip. Its a good idea to use workplanes and the existing, xy, xz, and yz planes fro sketching on initially when creating your parts. This is so constraining and putting together parts in assemblies is a lot easier when it comes to offset distances and especially centering non rounded parts.