The correct way to alter a pattern after fits

This image features in the new book (that will be out shortly) "How to spec and grade lingerie". It shows you the importance of after a fit, knowing and understanding your fabrics and patterns.

The briefs were made after an actual fit session with a client who wanted to increase the depth and widen the gusset at the front mid leg. 

correct way to alter a lingerie pattern

The brief on the left was altered by a pattern maker, one look though, you will see it doesn't look right. The one on the right is the pattern altered by myself after stopping the alterations going further, where I would have increase it.

Both briefs technically do the same job, they got increased by the amount the buyer wanted.

However by understanding that the satin on the front didn't stretch horizontally I was able to make the call of adding in the front and the back to allow a nice curve of the front leg.

If after your fits your lingerie is still looking wrong, start again, and add the measurements in differently to create the look and fit you wanted. With time you will be able to do this quickly.