Hi,

When a profile curve is not aligned directly towards standard views it's hard to edit the curve in site while keeping all the points in the same plan.

In this example a curve in the sweep is not align and it's kinda hard to tweak.



So, making a cplane is not easy as there is no xyz straight reference when you have curved objects like those.

It would be nice if cplane could align to a flat curve, the widest proportion of the curve being x and the other y.


Or maybe if the boundingbox command could have an option to make a 2d rectangle aligned to a flat planar curve, even if the profile is not aligned orthogonally... This way it would be easier to manually align the cplane.

Here bounding box make a cube.



Maybe there a way to do this I'm not aware of?

Marc

As you have yet the "flat curve", seems there is no problem for have the C plane!

Let point any external point of the curve as Origine
click the Xaxe and move/point to the "oposite point" of the first external point
click the Zaxe and move/point to the "vertical" of the first external point
that's all ;)

Ps If you are losted look all views, and you can even use the "helpers' lines"!

Hi Marc - so normally when placing the cplane if you pick a point on a general curve (planar or not), it will align the z axis of the plane to the curve's tangent direction.

That's so you can do things like stations along a central rail curve, something like this:




But if you snap on to a center point object snap on a circle for example, it will align the z axis to the circle's plane normal.

So possibly the easiest way to get what you want is to draw in a circle with "circle from 3 points", with each of the circle's points snapped on to that curve, that will put the circle in the same plane as the object and then you can place the cplane on to the circle's center point. The cplane's z axis will be aligned how you need it then from the start, and you can drag the x axis to point it towards the direction you want to have as the horizontal, it will pivot around the z axis.

You may find it easiest to place the 3 circle points in some localized area like this (possibly turn off straight snap):



and then move it around after that.


It would be nice to have an option to place the cplane in the same plane as a selected object, as a different way to place it than by picking a point, that's something that I could add in v3. But for the moment drawing in a circle should do the trick, let me know if it does not.

- Michael

Hi Pilou,

> Let point any external point of the curve as Origine
> click the Xaxe and move/point to the "oposite point" of the first external point
> click the Zaxe and move/point to the "vertical" of the first external point
> that's all ;)

Yup, this method will work, the only thing is after you have placed the x axis to be in the curve's plane, you will then want to do a single click on the x axis to mark it as the "primary axis" (you will see the little round end marker appear at its end), before you start dragging the z axis.

That will make the next drag of the z axis to be forced to only pivot around the x axis rather than it having free movement.

But it may be a little easier to draw in a circle as I mentioned above because then you don't have to do these rotations, snapping to the center point of the circle will place the z axis in its correct alignment from the start.

- Michael

So draw a circle will be more easy ;)

Hi Michael, well the circle trick works great, wish I'd thought of that one earlier!
Thanks!!

""It would be nice to have an option to place the cplane in the same plane as a selected object""

Indeed!

Hi Mr.Pilou, thanks for the tip!
But I get various results fiddling with the axes, I guess I'm not well accustomed with them.

Marc

Hi Marc, here's a demo of how the "axis manipulation" method works:




The way it works is after you place the initial point, only the z axis is in the plane, pointing along the curve's tangent direction.

So the second step after that is to grab the x axis and pull it around to point at some other spot on the same curve opposite the point you initially placed.

Now there are 2 axis directions in the same plane as the curve, which is good. But now you want to rotate the whole thing so that it is the x and y axes in the plane, not the x and z axes as it currently has.

So to do that, click once (instead of drag) on the x axis, you will see there that the dot shifts to it, that makes it the primary axis. Now you can grab the z axis and drag it to rotate it around the x axis, stop when it does an angle snap in a 90 degree increment.


But yes putting in a circle is less complicated.


But the above may give you more of an idea how the axis orientation picker thing works.


- Michael

@ Marc
you can see that the Michael animation is some like my method :D
After some training the New Axis function is some "performante" :)

Thanks Michael, I did not understand that to grab the manipulator by the axis rotate it, I was dragging the endpoints...

It's the first time I feel I should've read the instructions!

I get better results with Pilou's technique now...

Marc

Hi Marc,

> Thanks Michael, I did not understand that to grab the
> manipulator by the axis rotate it, I was dragging the
> endpoints...

It should actually give you the same result if you dragged by the endpoints - for this particular thing it works the same if you grab anywhere on the axis, including the end.

The part that gets a bit more complex though is the behavior of the "primary axis" - the one that is marked with the outline dot at the end. When you drag one of the other axis lines, the primary axis will remain unchanged and the other ones will only pivot around it.

If you drag on the primary axis, it has more free unconstrained rotation.

You can switch the primary axis by clicking on an axis instead of dragging on it.


When you initially place the widget, the z axis will start out as the primary axis.


- Michael

Hi Michael,

Yes, I understood the primary axis feature constrain in your first description.
Thanks for taking the time to point out that dragging on the end or middle does not matter.

Perhaps something like a quarter circle representing the axis rotation would be educational for people who are a bit challenged like me?

Maybe colors for the axis?
Just a thought...






Marc

Hi Marc,

> Perhaps something like a quarter circle representing the axis
> rotation would be educational for people who are a bit
> challenged like me?
>
> Maybe colors for the axis?
> Just a thought...

I could experiment with those in the future.

I rather like to keep things as much on the simple side as possible though, too many additional adornments and colors on the screen in general can sometimes cause different problems like distraction, or sometimes confusion about what the special meaning of the various colors are.

There's also a kind of general problem with axis colors that I've run into in the past, which is when the local grid axes of each viewport are colored with red for horizontal, and green for vertical, it tends to lead to confusion about why the front view for example has a green line when it is actually pointing up in the world z axis direction. That's another reason why I have tended to stay away from axis colors.

I may be able to kind of relax this avoidance in the future because it seems that I've been successful with moving way from the "local cplane in each viewport" model that I set up in Rhino to a more "global cplane" type system in MoI.

- Michael