Aligning 2D objects

I’m a newbie and I was loving the tool until I tried to perform what I would consider an obvious task - aligning 2 simple sketches to their centres. This is so that I may perform an accurate extrusion - it cannot afford to be be the slightest bit off centre. My approach is to create two planes and align the respective shapes on both snapping to their centre points bit this does not seem to be possible? How should this be accomplished?

I’ve spent half a day googling this and have found little of any help. I new to the tool so have I missed something as this must surely be a common requirement?


In Shapr3D, sketches are positioned using constraints. Can you share a screenshot of your example?

Thanks - What I want to do is really simple Once correctly positioned (the two objects centred on one another) I will extrude 2 solid shapes so I can cut a slot in the circular disc. If this is possible I will then create a ring rather than a disc and repeat the task.

Thanks for you prompt attention.

Something like this?

Hi and thanks. Close enough. If I knew how to model that aligning the objects on their centre points, I could model a part of what I need.

Extrude the cylinder first, then sketch on the top of it. You can move the rectangle to the center of the cylinder’s face.

With regard to actually making the slot, there are number of ways to achieve the same result…

With regard aligning the rectangle with the cylinder, there are a number of ways to achieve this.

In the first example I simply sketched the rectangle on top of the cylinder, moved it away the extruded to cut the slot.

In the second example I first created a construction plane and sketched a rectangle before extruding to cut the slot.

In both these examples I sketched the rectangle from centre.

In the third example I first created a rectangle away from the cylinder then used the translate took to snap the centre of the rectangle sketch to the top of the solid cylinder before moving it up then extruding to cut the slot.

Thanks Istvan. What I have found is that when I place an overlapping rectangle over a hollow cylinder, the rectangle breaks into 3 pieces, 2 outside the overlap and one inside the hollow part of the cylinder. Intuitively, I feel that it will prove a useful feature in my modelling, but can it be disabled?

No, it can’t be disabled. With the introducion of History-Based Modeling, we’ll provide an option to disable this behavior per sketch. Why do you want to disable it in this case?

You could select the rectangle with a bounding box to capture the entire rectangle, select face then extrude to cut slot…

Thanks Steve - that looks to be exactly what I’m after - I’ll give it a try.

Thanks again

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Hi - extruding the oblong to make a cuts excludes the ring structure itself - the bits I want to remove