Rvt 13: Driving Points Please

[dbroad]

I am trying to understand the concept of driving points and how to manipulate them. Wiki-help says to draw them on a spline and then to select them and to choose the option bar and choose "make driving. This doesn't seem to be valid any longer if it ever was.

In the conceptual mass environment there are two types of splines, one that goes through points and another that establishes the reference frame. The one that has points does not require separate driving points to be made because they are automaticaly made as the curve is drawn. The other spline type has no point elements associated with it, nor can I find a way to add driving points to it after the fact.

If a point is driving (created at the same time as the reference line/spline), then if the driving checkbox is unchecked, a warning dialog is generated and the line/spline disappears from that point. There is apparently no way to make that point driving again.

If a spline drawn through points is disolved, then all the points can be selected. When those points are selected, if the draw spline through points button is pushed, then the curve is drawn through all seleced points and they all change to driving.

Am I missing anything?

[constantin.stroescu]

you are speaking about the Spline Through Points and the Spline with Control Points

1.  Spline Through Points use Driving Points when it is created... If you select one of the Driving Points a tripod (x,y,z) will appear and if you move the point the curve follows the point and can be adjusted.

If you want to put another point on the curve , pick Point Element and then pick the curve .

The new created point belongs to the curve, it is called Hosted Point. If you select and try to move the Hosted Point it will move only along the curve without changing its path (in Properties>Measurement Type you can control the position of the point on the curve )

If you want to transform the Hosted Point into a Driving Point in order to can edit the curve more accurate you can do it by Make Point Driving comand .

Hosted Points are usefull when you want, for instance to make a sweep , shapes can be placed on the normal plane defined by these points and the curve as  a path.

2. Spline with Control Points  can be refined by Edit Spline > Add Control <>Delete Control  options. You can also place on it Hosted Points ( that can be used for sweep purposes) but , of course that points can not be turned in Driving Points because the curve is not defined this way.

So :

DRIVING POINTS

HOSTED POINTS

and FREE POINTS  that can be freeley moved ...if you select a row of free points and then comand Spline Through Points...they will be conected and transformed in Driving Points. Free Points can also be conected with reference lines and so can obtain by Create Form ,volumes or surfaces......

[dbroad]

Thanks.

I guess my point is the the help files aren't that helpful.  It explains a method for adding driving points that misses the prime prerequisite.  IOW, you cannot add driving points to a line unless that line has first been created as "3D snappable" and therefore already has some driving points.  If a line is not "3D snappable", then it cannot be made so later.  If the line is "3D...", then placing a point on that line and then selecting the point allows you to make it "driving".  If it is not already "3D", then driving points are irrelevant and not supported.  This important beginner information is missing from the help files.

[KDolley · Accepted solution]

Hello.

I'm sorry the help content was confusing and/or misleading. I have adjusted that topic to be more specific so that it will be more helpful for future visitors. Thanks for the feedback as we are always looking to improve our learning content where we can. For future reference, please feel free to comment right in the wiki. We monitor all wiki activity and respond as quickly as possible. 

Thanks again for letting us know how we can improve things and contributing to our helpful community.

[dbroad]

Thanks Kevin.  Although that link doesn't work yet for me, I am sure changes will help others.  Here is what I am posting for my students:

During the creation of conceptual masses, the draw panel allows you to draw the generative geometry in several ways. While drawing, the options bar indicates the choices available. One important option is the checkmark "3D snappable". If lines are added that are "3D.." then driving points will be added during their creation and other driving points can be added later. If the "3D.." checkbox is left empty, then the lines are intended to be hosted by a reference plane and cannot be made "3D.." later. So if a line has no driving points attached, you cannot add driving points. If driving points are deleted from a "3D.." line, then the segments/curve attached to that driving point will disappear. If a "3D.." line is dissolved, then it can only be recreated by drawing new "3D.." lines through the remaining "Free points".

Hosted points can be created on "3D.." or 2D lines. They appear smaller than free points or driving points. Their alignment is dependent on the line that hosts them. Hosted points can only be moved along the lines that host them. The host for a hosted point can also be changed by using the "Change host" button. Hosted points can also be "Hosted by Intersection". If hosted at the intersection they can be toggled to align with either connecting segment. To get them off the intersection, you must use the "Pick New Host" button when the point is selected.