topic Re: Solid element operations on a target using only one skin in a multi-skin composite operator in Modeling

Solid element operations on a target using only one skin in a multi-skin composite operator

Paul King — Wed, 31 May 2023 12:40:17 GMT

Has anyone come up with a clever way to perform solid element upwards subtract extrusion operations on a target using only one skin in a multi-skin composite operator.

Materials in the composite operator element that I don't want to cut the target are set with lower materials priority than the target element material, and the material that I do want to act as a cutter has higher materials priority - however when I attempt to use the operator on the target to do an upwards subtraction, the low priority material nevertheless cuts the target anyway.

No doubt I am missing something obvious here, but can anyone assist?

Crude markup below

This is a composite roof consisting of a plywood skin on an insulation skin, where I want only the plywood part to cut the rafters with upwards extrusion.

The red dots indicate extent of desired cutting of the rafters, and the green dots indicate the base of the rafters that should be left uncut by the operator element.

What actually happens is that the base of the cut is from the base of the insulation, even though materials priority of insulation is lower than for the rafters it is cutting.

Re: Solid element operations on a target using only one skin in a multi-skin composite operator

Paul King — Wed, 31 May 2023 12:53:08 GMT

Thanks Eduardo - that would be a valid workaround - but there are a lot of beams , and a lot of notching of beams in this project, and relying on manually sizing each notch/beam segment height under sloping roof elements would mean the cut notches could not update automatically when the roofing element moves, changes slope or size.

In this case the roofing element represents the base of a gutter (one of many), each of which is set to a small fall.

Re: Solid element operations on a target using only one skin in a multi-skin composite operator

Eduardo Rolon — Wed, 31 May 2023 13:04:17 GMT

After more careful though I deleted my comment (and you answered too fast) since it is a roof condition (not a slab) and I presumed your comment.

Re: Solid element operations on a target using only one skin in a multi-skin composite operator

Eduardo Rolon — Wed, 31 May 2023 13:19:24 GMT

Using Openings might be an option since I don't think you can SEO with skins.

Re: Solid element operations on a target using only one skin in a multi-skin composite operator

Eduardo Rolon — Wed, 31 May 2023 13:13:50 GMT

The bottom of the opening matches the Roof Pitch and it is relatively easy to edit in section

Re: Solid element operations on a target using only one skin in a multi-skin composite operator

Paul King — Wed, 31 May 2023 13:20:15 GMT

Hi, yes, it could be an option for someone with an already resolved design - but the design is currently fluid, and I need a way to iterate to test the impact of changes to roof fall geometry on beam notching - with a hundred beams, and many roof segments, and many ways to lay the roof and gutters. The whole aim of the exercise for me is to let ArchiCAD do the work for each iteration.

I could have sworn that materials priority was supposed to take precedence when it come to SEO

Re: Solid element operations on a target using only one skin in a multi-skin composite operator

Eduardo Rolon — Wed, 31 May 2023 13:29:13 GMT

In that case then it might be easier to model the roof separately instead of using a composite.

Remember that Roofs do not work well with BMats which is the reason for the connect command.

Re: Solid element operations on a target using only one skin in a multi-skin composite operator

Paul King — Wed, 31 May 2023 13:34:37 GMT

OK, the plot thickens - when I just view the roof element in 3D, materials priority is not leaving holes in the insulation where the beams pass through it. So something else may be underlying the issue

The beams and the roof are on the same intersection priority in the displayed later combination, for what that is worth, but I must be missing something, because it seems material priority is not working at all.

Re: Solid element operations on a target using only one skin in a multi-skin composite operator

Paul King — Wed, 31 May 2023 13:58:49 GMT

OK, a nasty workaround was to add another invisible skin on top of the roof composite that has materials priority 999, then to select all beams and roofs and use Connect/Merge Elements - this gave the intended result in 3D (visually) - but then of course roof level markers give the wrong readings....

Yes, another workaround would be to use a simple roof rather than a composite roof for the cutting, and make a lower down copy of this, changed to insulation material as the insulation layer - but then I would have two roofs to manage through each iteration I submit for discussion, and I would get a geometrically distorted result if I simply copied the same roof down and changed materials - because not all roof pitches are the same, and thickness of material needs to be measured normal to slope, not vertically - so junctions between roof planes at different pitches would need to shift around and be offset between one skin and the next - a horror show!

Re: Solid element operations on a target using only one skin in a multi-skin composite operator

Eduardo Rolon — Wed, 31 May 2023 13:50:49 GMT

Remember the Connect-> Merge Command

The 2 cutting the insulation are merged to the roof.

Re: Solid element operations on a target using only one skin in a multi-skin composite operator

Eduardo Rolon — Wed, 31 May 2023 14:22:59 GMT

Strong Air BMat for the win…

Re: Solid element operations on a target using only one skin in a multi-skin composite operator

Erwin Edel — Thu, 01 Jun 2023 07:13:06 GMT

Not sure if it's been suggested, but you can use a segmented beam, which you can either save as a favourite or use the syringe to transfer element settings to other beams.

Either set (or change) the reference axis to bottom, or make a complexprofile that you can stretch from the top or just give it the fixed size needed.

If you give the notch and the start of the beam a fixed size and set the rest to '100%', you should have a stretchy solution.

Re: Solid element operations on a target using only one skin in a multi-skin composite operator

Eduardo Rolon — Thu, 01 Jun 2023 11:32:30 GMT

That was my initial recommendation that I deleted (and shouldn't have) reason that it does not work is that it needs to be manually updated if the roff pitch changes, if I understood correctly.

Re: Solid element operations on a target using only one skin in a multi-skin composite operator

Paul King — Thu, 01 Jun 2023 11:51:32 GMT

Yes, that was the problem. Far too many beams being notched by roofs to do each one manually, for each iteration of roof fall geometry and beam depth being considered.

Re: Solid element operations on a target using only one skin in a multi-skin composite operator

Erwin Edel — Mon, 05 Jun 2023 07:04:45 GMT

If the notch is the same, the total lenght can be different. You can just select all your existing beams and add the notch, as long as some part of the beam has no defined length. Or you can use the Adjust function etc afterwards to connect your beams as you normally would.

That's what I tried to show with the screenshot. My notch there is 30 mm, the rest is 100%. The beam can be any lenght (greater than 30 mm obviously), but the notch will stay the same. You can stretch it as any other beam, it just has a fixed size part.