Underquilt calculator question

[Shirley]

Playing with Catslats underquilt calculator and it shows the inside and the outside to be the same length. The width was 12" different. Is this right or am I doing something wrong?

[SnrMoment]

Differential cut most likely.

[Caminante]

It is correct, assuming you've entered your input data correctly. Mine had a width differential of ~11.7". The width of the outer shell needs to be wider to account for the sidewalls and the "puffiness" of the baffles. The inner shell should lay flat, the outer shell handles all of the contouring.

I suppose you could also consider lengthening the outer shell to have more square ends as opposed to tapered, but I didn't bother and can't tell the difference lengthwise.

[Shirley]

So inner and outer being the same length is fine?

[tnrdnck]

So inner and outer being the same length is fine?

Yes

[Boston]

So inner and outer being the same length is fine?

Generally yes. If you want a differential in the length dimension just add your baffle height to the outer shell on each end.

My version of CatSplats calc will do this, and allows you to add seam allowance. You can find it in the same thread.