Various Bezier Curve Issues

NOTE: I've submitted this bug for Eovia's attention but would like to spread the word as well so that other people can verify this behavior.

I was playing around with V1.21's Bezier Curve tool when I ran into this peculiar behavior (make sure you have either Restricted or Full DG enabled):

1. Create a Bezier Curve and "drop" it (i.e., press <ENTER>).

2. Select the Bezier Curve and execute the Stretch tool. Bezier handle look fine and display correctly. Drop the Stretch tool by pressing <ESC> or <ENTER>.

3. In the Dynamic Geometry panel, select the Bezier Curve's control curve.

4. Go into Vertex Select mode

5. Enable the Translate manipulator and move at least one vertex from the control curve.

6. Execute the Stretch tool and try to move any of the Bezier Curves control points. Although the Bezier Curve is updated, the handles and control points are not.

That's one bug. Exiting and re-invoking the Stretch tool seems to solve this but this is still disconcerting. Now, here is where it gets really strange:

7. Select the Bezier Curve and execute Insert Points. Hex should show the control curve. Add at least one control vertex anywhere along the control curve.

8. Execute the Stretch tool and observe what happens to the Bezier Curve's control handles. At this point, moving any control point or handle will mess up the curve. The two images show the resulting control curve after inserting a point and how it affects the Bezier handles when the Stretch tool is used after the fact.

I've also noticed some issues with trying to edit the Bezier Curve using the Stretch tool:

1. If the handles at a particular control point are not tangent, you cannot reset the tangency of the handles using Stretch.

2. If the handles at a particular control point are tangent, you cannot break the tangency of the handles using Stretch.

3. If the handles at a particular control point are not visible, you cannot make them appear using Stretch.

4. If the handles at a particular control point are visible, you cannot hide them using Stretch.

I feel that the Stretch tool should offer the same (editing) control over Bezier Curves as the original Bezier tool does when the curve was created.

Let me know if these things warrant a format bug report on the Eovia website or if anyone has the same results.

Lastly, this is more of a request than anything else: can we have control point Bias and Tension controls for the Interpolated and Spline Curves?

[bwtr]

I have been playing with the beziers all this morning and frequently looking at the Help files. I will not be surprised that the advice you get is that it is not bugs but trying to do things other than the way Hex is designed for! I went to both Photoshop and Illustrator to see the difference and I think it's the Hex "way" thats hard to get used to.

I have serious doubts that this behavior can be explained by going against Hexagon's conventions. This is an outright bug because we should be able to add control points to Bezier curves- every package I've worked with, either 2D or 3D, that supported Bezier curves in any shape or form allow the user to add/remove control points without adversely affecting normal operations.

Also, Hexagon's current implementation does not allow uses to append curves to the begining or end of an existing Bezier curve without converting the Bezier curve into either an Inetpolated or B-Spline curve. Once this happens, we loose the ability to add kinks and discontinuities to the curve without unnecessarily adding a lot of extraneous control points. In fact, because Hexagon's curve implementation doesn't support tension and bias parameters for Interpolated and B-Spline curves, Bezier curves are the only way to efficiently add kinks and corners to a curve.

[derk]

I agree that the bezier curve is not well implemented in Hexagon. If you work from an original drawing and try to match curves such as cross sections in Hexagon, this is pretty much impossible. This makes Hexagon much less a professional drawing / modeler tool as it could have been. In the Carrara Spline modeler we have true bezier curves, yet here we cannot use a background picture in the spline modeler. Not good

Derk

[BilloX]

Hi all,

Yes AmbiDextrose, you are perfectly right: there are defects, limitations and lacks in the current implementation of the Bezier curves in Hexagon (1.21).

Although I cannot commit that all lacks will be solved soon, be sure all the bugs you reported are in the development team's list.
But, as usual, it's a matter of priority - hey, sounds like something frequently answered by Eovia / other software makers - doesn't?

No doubt anyway these problems will be addressed in future releases and / or patches. And thanks for reporting them!

- Laurent / Eovia