Opening Tool, Custom Edge

[thesleepofreason]

Using Subtract from Polygon to create an opening in a roof (or slab) gives control of the angle and surface of each individual edge. Using the opening tool does not - this despite the tool being updated in AC28 to work on roofs where angle control often individual edges often is needed.

Inconsistencies like this makes it a pain to work in AC and it is really disappointing to see them introduced through with new tools (which is unlikely to get any more developments in the near future).

[Barry Kelly]

Both these options work in completely different ways.

Subtracting a polygon, you are redefining the geometry of the roof/slab and creating new edges, for which you can control the angle.

Using the opening tool, you are just creating a tube that is subtracted via a Solid Element Operation.

This does not create separate edges in the roof/slab.

You would have to adjust the angle of the sides of the tube (which you can't), and if you could that would be very problematic where the opening associates to multiple elements.

I am not saying your wish is invalid.

I would be great if this could work.

Just trying to explain why it doesn't work at present.

The opening tool would have to create actual edges in the roof/slab, and I am not sure if this could be dynamic for when the opening is moved, resized or reshaped.

Food for thought.

I wonder if there could be a solution for this?

Barry.

[thesleepofreason]

I do not agree that they work in completely different ways. Yes, the opening tool seem to be working by subtracting an extruded shape which locks the angle of the opening edges relative to the extrusion vector. But fundamentally both tool defines the opening by a shape drawn on a plane. The difference is that while the subtract from polygon tool is limited to drawing the shape on the elements reference plane, the opening tool can draw it on any chosen plane and have it projected to the elements reference plane. Both results in nodes on the element surface and as it is possible to manually draw a shape shape for subtract from polygon snapped to the projected shape of the opening tool, thus creating individual edges, it is likely this could be done automatically. 

The extrusion method is of course very intuitive and useful for cases with void openings and but I don't really see it as a justification for having to rely on different tools for modelling openings, especially not as one is inferior in terms of parametric and dynamic modelling and information management. No - this rather seems as yet another case of fragmented development without a clear strategy nor understanding of the software or how it is used in everyday modelling workflows.