Any question answered...

how do you measure an actual sloping top tube length on a frame in a cad program using the other usual measurements, such as slope angle............... ?

if no such formula exists what measurements would a frame builder need to know to cut the tube to the right size while building a frame?

It'll be something Pythagorasy, with the ETT and some angles or suttin. That or draw it out, or at least a scale version. A frame builder should know really.

S'just trigonometry, unless I'm misunderstanding you.

Snottyotter and alfie tag team shit maths crack squad gang!

Boom, I'll let you take this one.

You do the maths, I'll do the crack.

Fine, but I'll take the crack next time. What measurements do you have?

About 5g.

Ok, save me 2.5

How much do I smoke out of the 5 to leave you with that?

5/10ths

Wait, one of Imogens book's goes to 10, I'll read that.

Rep!

Otters hands look scarily human.

"Otters hands are soooo cute, almost human."

I know, it's scary.

how do you measure an actual sloping top tube length on a frame in a cad program using the other usual measurements, such as slope angle............... ?

if no such formula exists what measurements would a frame builder need to know to cut the tube to the right size while building a frame?

if you have the ETT it's pretty straightforward. If not, what measurements do you have?

Sloping top tube distance = ETT/cos(slope angle)

Just realised that'll only work if the ETT measures just the horizontal distance from the headtube/top tube to the seat/tube/top tube. One sec...

Right, so the sloping top tube distance is equal to:

(ETT - xsin(90- seat tube angle)/(cos(slope angle of top tube))

x = distance from where the ETT line crosses the seatpost to seatpost cluster

how do you measure an actual sloping top tube length on a frame in a cad program using the other usual measurements, such as slope angle............... ?

if no such formula exists what measurements would a frame builder need to know to cut the tube to the right size while building a frame?

Use the aligned dimension tool

Also that ^

I assumed you wanted it in terms of known values.

Surely a tape measure or an accurate drawing is enough for a frame builder to know the top tube length.

Frame builders love a bit of trig.

Are these forks bent back?