Visio Guy

I've been using Visio 2000 to create electrical diagrams and for some basic constructural drawings.

Currently I'm drawing some basic plans to build a shed outbuilding.

I'm able to create basic shed drawings using an architectural scale of 1 inch to 1 foot.

While trying to create  drawings with floor and roof trusses @ 16 inch on center, I'm unable to get vertical feet and inches to be equal the the drawing vertical scale.

I end up with too many 16 OC floor joists for a 12 foot long floor. I've tried various page sizes and scales but often the horizontal size becomes out of proportion to the vertical.

Which later versions of Visio would work better for this type of constructural drawing. Do any have an "on center" as part of the page and scale configuration?