Custom Barrel Roofslab problem

[BBP-Arch]

So I made a barrel roof by creating the form from solids and then converted it to a roofslab...worked great. Why then, after it's done, can't I edit this new roofslab? I can't lengthen it or shorten it?  Although I haven't tried yet, but can I cut a dormer into it? Or is it strictly boolean from here out?

[R_Tweed]

Yes, boolean operations or general solid editing would be required.

When you convert a solid to a roof slab, the resulting slab is created using the solid as a basis for plan and converts it to a mass element used as a body modifier with replacement.  Roof slabs can only be planer in order to be adjustable.  Converting a closed polyline would be the closest to having something editable which would not be a Barrel.  The dormer won't work for the barrel for the same reasons.  It trims, and makes a hole to accomplish it's task. None of those are available with a body modifier.

If you edit the body modifier, the mass element editing will be available and the grip shown below will allow the barrel to be lengthened in place.

When you make the slab from the solid, the mass element resolution is effected by the settings below.

I've attached my example dwg for reference.

[BBP-Arch]

Thanks for the info!!

[freddyalexander3366]

It sounds like once you converted the form into a roofslab, it became a "finished" element, which limits its editability. Typically, once you convert a solid form to a roofslab, it's no longer as flexible as it was before. You might not be able to directly lengthen or shorten it, but you should still be able to perform cuts or boolean operations like adding a dormer. You could also try splitting or trimming the slab using other tools, but yeah, editing the shape after the conversion can be a bit tricky.