Equations and Variables — Along with Constraints Features


Anyone making any interesting use of or combining constraints and variables/equations, and how?


Am still exploring how to overcome an issue I'm having ~ "Curve(s) not planar" when trying to affix the Coincident Constraint to a short line I want to be above and perpendicular to a longer baseline (and the display screen/user) but that farther-down baseline line is parallel to the screen.

Between them is a line perpendicular to the baseline. It successfully can be made Midpoint, Equal, and Perpendicular Constraint constrained. Although Coincidental Constraint works, I find it is unnecessary since Midpoint and Perpendicular give me what I need.

The baseline is not locked, but is itself Dimension Constraint constrained. To keep the left and right ends from moving, and only the right-hand sode is allowed to slide, I Coincident Constraint constrain that curve to a small "anchoring" or place-fixing curve which is locked in place.

Looking at the screen, the only curves that move as desired are those parallel to the screen. This view is what I'm considering a side view.

The one curve that defies me and to me defies logic is the perpendicular curve that I want viewable in top view and in the front/rear views.

I'm soon going to try to first or multiple-fails-tries again try a triangle that is perpendicular to the viewed curves. Circles no matter what orientation refuse to be made coincident. This failure means surface and solid geometry I want to make be coincident to the endpoints of the perpendicular curve (would be invisible to the viewer looking at the screen if the control points are turned off) can't be made responsive to the Dimension Constraint.

When I Dimension Constraint edit the horizontal curve to increase or decrease its length, the applied Equal Constraint works as desired to change the length, or in this usage, height of the vertical. I want the perpendicular curve to be Midpoint, and Perpendicular Constraint constrained.

Ultimately, I've so far gotten a collection or a chain of horizontal (to screen), Coincident Constraint constrained curves to be shofted left and right. Some I give Dimension Constraints so they retain fixed lengths, but some I gove non-constraining dimensions so the freely resize but report their lengths. The right most curve's right side endpoint is Coincidental Constraint constrained to a little curve that itself is locked. An alternative construction leaves unlocked the right-most curve, so I can explore longer chains of curves. Each segment in the chain has its own Equal, Perpendicular, Midpoint Constraint constrained curve.

So, manually editing some Dimension Constraint values will act to increase the height of the vertical. I want to later affix either a control point apline or an interpolated spline, or a circle-based sphere. Ultimately, if a spinner were available to the user of SharkCAD, the user could mouse wheel-dial the values up and down, causing the spheres to change diameter, go up and down along the perpendicular-to-screen curve that would be constrained coincidentall or midpoint to the vertical.


But, so far, circles, boxes, and triangles are unable to be geometry helping affix the perpendicular to the vertical curve that does behave.

And, this is where I'm vexed deeply, failing at everything I can think of

If I can achieve that, I want to then attach variables or equations so I can make some of the curves (namely, the perpendicular-to-screen) be not just Equal Constraint constrained, but have adjustable or variable lengths.

Any advice would be greatly appreciated.

Thanks!