This is my first post. I’m an architect and I have limited experience with Rhino.
I’m modeling a hollow clay brick and I’m encountering issues with drawing the curve for the ribs (I plan to extrude the curve later). I’m using a Control Point Curve, but not all points are creating the same curvature. After running the CurvatureGraph analysis, it’s evident that there are some issues. As shown in the attached image, most of the points are fine, but only one corner (bottom right) is correct.
I’d like to learn how to match the radii of the control points.
Attaching the Rhino file and providing additional information.
The curve was created using the Control Point Curve tool. After completing the initial drawing, I added a few additional points using the Inser Knot command.
Your problem is that all the control points are not on the same plane. Look at your curve from a side view.
You can turn on the control points select them all and use projectToCplane to make them all at the same level. Use the delete input option or you will get 2 curves - one good and one bad.
I’m almost there, the curve now looks almost as it should. The sides are fine, but I’m still noticing issues with the corners, except for the bottom right corner.
Could you help me identify what might be causing this?
If I understood correctly, this is going to be a brick not a sports car.
I’m not qualified to advise anyone on what a brick should look like.
I would suggest go ahead and make the surface and see what it looks like in a shaded view.
You can make the surface with history enabled and use Rhino’s Nudge feature with the arrow keys to move control points of the curve to edit the surface.
One thing you might try is to split off the lower right quadrant of the outline (the one with the corner you like) being very careful to split it at the point of symmetry on each side, then mirror it vertically and horizontally. Then join the 4 pieces and add the holes.
I’m still curious about why not all segments of the curve behaved as expected. In the original curve, all the points are correctly positioned, but each of the 4 corners are slightly different. Running the CurvatureGraph command confirms that the curve segments have varying radii.
Oh now I see what you are asking about. You already provided the answer to that question. You said you inserted knots into the curve.
When you created the curve as a “Control Point Curve” it was a curve with uniform knots. After you added knots it no longer was. This means the distribution of spans is no longer evenly spaced.
You can run the MakeUniform command on the curve to make the curve uniform again without changing the control point positioning.
