Three "How do you...?" Questions

[vegipete]

Greetings!

I've been using MiniCAD for a while, about 15 years. We never bothered to upgrade past MiniCAD 7 because it does enough for our purposes, which is primarily machine design. I have three things that have annoyed/vexed me for many a year that I'd like to know others' thoughts about.

1) Back around MCv4 or 5, it was possible to specify the exact "Convert to Lines" resolution. Later versions merely allow a choice between "Low, Medium, High and Very High." Is there any way to get back the previous flexibility?

2) Is there a way to get MiniPascal to ACCURATELY report the coordinates of the ends of an arc?

3) Is there a way to draw a circle that is tangent to 3 other entities? For example, draw two intersecting lines and one arbitrary circle. (This circle may or may not be tangent to one or both of the lines, and/or the intersection of the lines may be inside or outside of the circle.) Now, how does one draw the various circles, of which there could be up to 8, that are tangent to both lines and the circle? (Extend the lines as required.) I have never yet figured out a geometrical way of performing this operation in MiniCAD, although an interesting iterative method presented itself.

My thanks to creative users who have interesting insights on any of these questions.

P.

[MullinRJ]

1) There is an object preference that can be set, SetPrefInt(55, #);

where # is a power of 2 and #/2 is the number of segments a full circle will be divided into. SetPrefInt came into use in VW8, but I don't know when 55 was made available.

2) Yes. Some analytical geometry is required.

3) Yes. Are you lookng for a manual method or a VS solution? If the latter, more analytical geometry is required, but I have used VS to solve the one-circle-tangent-to-3-other-circles problem. As you mention, up to 8 solutions are possible. With different colors assigned to the various solutions, it's quite pleasing to the eye. I haven't tried it for two arbitrary objects (lines) and a circle, but it should be solvable.

Solutions for 3 circle tangents are posted on the internet. I found some after I did all the algebra. You might try looking for other algorithms there. Scripting is a lot easier with a well defined plan, but a lot less fun.

Raymond

[vegipete]

Thanks for the ideas.

1) Ah, now that's cool. Gotta look into that.

2) Well, none of the analytical geometry I've tried over the years has worked well. I currently use a combination of the HCenter(), GetArc() and HPerim() functions, but the results are sloppy. Which is why I'm hoping for a better solution.

3) I suppose the manual method is of interest. I can crunch a VS solution if I really need to, but a manual method would get the most use. I've used other CAD software that had little problem drawing tangent circles based on selecting 3 entities. (This problem originally arose because I was trying to fit a pipe into the cavity formed by a drum pushed into the corner of a box.)