How to determine angles for building an internal stud wall in a window bay

[zachmbutcher]

I have a six window bay and as part of some improvements removed the inner wall and this now needs to be rebuilt and will eventually have a window seat inside the bay.

I’m struggling how to work out the angles for the faceted stud wall for the internal wall. I want the angles to be aligned to the window mullions.

Originally I found the centre of the bay and then ran my laser through the centre point and through the centre of each mullion. It visually looked ok.

But then I thought I’d double check on line how to do it. Have really struggled to find anything concrete and resorted to checking what ol’ ChatGPT would suggest and this is now making me more confused.

According to ChatGPT my way was radial geometry and not correct option for the bay. Left wall is shorter than right wall and ChatGPT said I should make a datum from the centre mullion. Then find the centre of the next one and offset with perpendicular line to get the angle. Draw lines on floor and cut sole plate to match but my issue is visually the first cuts on either side of the datum line are not even and I’m worried the lines won’t match vertically through the mullion.

I didn’t want to just trust AI but I can’t find any other videos/pictures or forums that show how to do it and no matter my variation of question or deeper dive, ChatGPT will not change its instructions.

How would you go about laying out the wood for the sole plate of the internal stud ensuring that the angle of the mullion aligns into the new stud wall

Adding some pics which hopefully help in my waffly explanation/question

Pic1 of bay overall and windows
Pic2 is the Red Cross I found in centre of bay that I used to determine angles - ChatGPT said this is radial geometry and wrong
Pic3 with red dashed lines is the angles I first made all running back through centre X
Pic4 blue lines ChatGPT instructions of making a datum through centre and running a laser down centre of each mullion

Thanks all

 

[DAZB]

"Originally I found the centre of the bay and then ran my laser through the centre point and through the centre of each mullion. It visually looked ok."
You should have stopped at that point as I think you have committed a classic case of overthinking it. You could struggle on and possibly achieve a mathematically correct result but if you are happy with the way you first did it then I would go with that and spend the rest of the day doing something else. That is merely my opinion and no doubt someone will offer the mathematical answer you are looking for but it is Xmas and people are busy so depends on how soon you plan on doing the job.

 

[Koolpc]

Never used Angels for any building work. Unless they helped unbeknownst to me!

 

[cdbe]

I think I'd just do it curved.

 

[zachmbutcher]

Never used Angels for any building work. Unless they helped unbeknownst to me!

Good spot cheers

 

[^woody^]

It looks to me that the centre marked in red is not actually the centre of the circle which the bay segment is part of.

 

[Tigercubrider]

Sometimes “right” looks wrong and “wrong” looks right.
I would do it by eye, template it with hardboard/thin MDF

 

[IJWS15]

Cut a piece of board with parallel long edges, one edge to sit on the window frame and the width that will match where the inside edge of the framing will be. Use this and a level/plumb line to mark the inside of the frame on the floor. Of course this assumes the window angles are right.

 

[zachmbutcher]

I think I'd just do it curved.

That I guess would be an option I just didn’t really fancy it curved so was trying for faceted to match

 

[zachmbutcher]

It looks to me that the centre marked in red is not actually the centre of the circle which the bay segment is part of.

Yes it’s not the centre of what a full circle would be. It’s effectively on a chord? (Really dragging up my gcse maths)