chook: tangents

[Duckman]

is there a chook function that I can use to return something like a tangent to a curve at a specific point?

 

I will have an arc spcified by XxYyIiJj, and will need to be creating tangents at either ends of this arc.

 

any ideas?

 

thanks!

[Bullines]

I haven't seen a method in the SDK so I've just ended up doing it the old fashioned way.

[ProductDevelopmentGuy]

Analyze/Dynamic gives you tangent vector info. Maybe you can use that.

PDG

[camguy]

This operation can be done using a macro, which you can assign to the tool bar, or use a shortcut on the keyboard. First, create an arc segment on the screen, then start the macro record button. then

create line end points, end point, center

create line end points, end point, center

create line, tangent through a point, pick line, end point of line, and select which line to keep.

repeat for next line.

stop macro record. Now open up the macro in the editor, and you will see the last 2 items as

[clprppt]

ENT

POINT

LENGTH = 1.0 <- CHANGE TO -> LENGTH = ?

LINE = E* <- CHANGE TO -> LINE = ?

This will prompt you to enter the length of the line, and select which line to keep. If the line length is constant, then leave the length as shown, or change it to whatever length you want.

Note- you can create the prompt during the macro record, but i find it easier to edit the macro after. hope this helps