Question re: modeling, creating voids, or cutting geometry into walls:

[Philip_ATX]

I am a student who has been taught the basics, and trying to delve a bit deeper.  (I have not been taught to model forms, so talk to me like I am a baby just learning this language please...)

I have challenged myself to model curved walls, penetrated by arched openings, and supported by Tuscan-style columns.  (I have an issue with my column, but back to that later...)

The arches thus have compound curves.

In trying to find out how to create the arches in curved walls, to create wall penetrations with a taper, I thought the best approach would be to create a "void-form" as a generic model (created as a blend with two separate arch shapes, reflecting the narrowing of the arch towards the inside of the wall's curvature, but edges *not* quite perpendicular to wall face.)

I hope that makes sense.  Please see the attached, regardless, to help clarify.  The generic model "Void-Form" is here imported and selected as shown by blue lines.  (I won't tell you how long it took me to figure out I needed to use the "Component" tool in the architecture panel to import that!)

My problem now is that, while I can subtract the overlapping volume of the wall from my imported component, I *cannot* use this model to subtract the desired void from the wall.

Is this a setting on my generic model that precludes my ability to use it to subtract?  A setting on the wall? Does the fact that a wall is essentially a spline-in-plan with assigned thickness and height preclude treating it as a 3-D form?  (If so, what workaround is proposed?)

Second minor issue, I did a revolve to create the column (after deciding on online tutorial with blends was unnecessarily cumbersome and demanded too many circles to control the bulges caused by the interpolations)  but where I tried to join two line styles in the profile, I have a seam (1/3 up column where entasis begins).  I don't know why I couldn't join the two lines, but wonder if I need to redo with one long spline to avoid the "seam" or if they should be able to be joined?  (below point of entasis was a straight line, and is a spline above)

Thanks in advance!

[Edited/replaced initial image to help clarify]

[RLY_15 · Accepted solution]

https://forums.autodesk.com/t5/revit-architecture-forum/non-rectangular-opening-on-a-curved-wall/td-...

This thread does a pretty good job explaining the methodology you need for the opening.

It does make sense for a join between a straight line and a spline to leave a seam mark unless the spline endpoint is tangent to the straight. Is the seam only visible in wireform, or can you see it in Shaded/Realistic? 

[Philip_ATX]

The seam shows in shaded/realistic as well.  (I was avoiding sharing this image so as to avert the obvious, "Dude, you didn't account for the extent of the convex belly of your wall" discussion!  LOL)  Yeah...  I assume I needed to create a single spline, but wanted to create a hard "stop" to the curvature.  Perhaps the two profile lines are not perfectly cotangent (is that the term I am looking for?) despite my efforts.

Will review your provided thread-link and follow up!  Thanks!

[Philip_ATX]

I had considered this approach, but this will create lines at ends of arch (in plan) that radiate toward the center.   I wanted a little more control, such the the ends of each arch would be parallel to the abacus (the square cap atop the column) and have consistent offsets from the abacus.  The taper is a slight deviation from what I intended.

What I was aiming for in plan (albeit not deep enough to cut entirely through outside face of wall) is below:

Is there a reason I can not use the generic model to cut?  The cut tool won't even allow me to select the "Arch-void" generic model after the wall, but will permit the opposite operation, cutting a void out of my temporary generic model.

[Philip_ATX]

trying to directly convert an in-place model to a void form...

results in the following error: