Transition curve problem

[Phil O]

Hi Martin,

I was in the process of altering a 1st transition radius and adjusted the mouse response to extra fine, and zoomed in, when I got the following up on the screen.

I saved the templates and closed Templot and the reopened it and the problem is still there.

Lenovo laptop, using Win 10.

Many Thanks

 

[Martin Wynne]

@Phil O

Hi Phil,

This is a known effect -- that's quite a mild one, see:

https://85a.uk/templot/archive/topics/topic_1391.php

It means the transition curve is too gentle for the Templot maths. The rate of change of radius is too low along the transition zone.

Generally it means there is no need to use a transition curve there. To fix it, you can:

use a simple link instead (recommended), or

shorten the transition zone, or

set a bigger difference between the two radii, or

use a normal constant radius curve and adjust the connecting templates a fraction, or

something else.

cheers,

Martin.

 

[Phil O]

Thanks Martin

The difference was about 8mm.
I've had the all gone haywire experience, many years ago and was unsure if it was the same thing or not.

 

[Martin Wynne]

I've had the all gone haywire experience, many years ago and was unsure if it was the same thing or not.

Hi Phil,

It's certain that it could be fixed with some changes to my numerical algorithms.

When I made Templot open-source, I was expecting that would be just the sort of thing where folks would want to jump in and make improvements, gently pointing out the flaws in my transition maths code -- I'm sure AutoCad doesn't flash matchsticks and broken glass across the screen! But so far I'm not aware of anyone being interested.

The T3 open-source version of Templot uses 64-bit doubles instead of 80-bit extended-type floats, for compatibility. So I would think the effect is much worse on there, although I haven't tried it.

cheers,

Martin.

 

[Phil O]

Martin,

The coding stuff is well out of my comfort zone.