Rhino 6 documentation bugs

[davidcockey]

@andrew.nowicki

If you use the Line>Perpendicular command without the FromFirstPoint option, you expect the line to be either drawn in the construction plane, or in the curve plane, but the line is actually drawn in random plane.

Not a random plane. It is drawn in a plane parallel to the construction plane of the active viewport. The default Perspective viewport construction plane is aligned with the World XY axis.

@andrew.nowicki

We need new feature:

1. If the Line>Perpendicular command is used without the FromFirstPoint option, and perspective viewport is active, the line is drawn in the curve plane.

Only planar curves have an associated “curve plane”. Non-planar curves do not have an associated “curve plane”.

@andrew.nowicki

If the Line>Perpendicular command is used without the FromFirstPoint option, and ortho viewport is active, the line is drawn in the construction plane.

A perpendicular line can only be drawn in the construction plane if the construction plane is normal to the curve. If the construction plane is not normal to the curve a perpendicular line can be drawn in a plane parallel to the construction plane. This is the current behavior.

[andrew.nowicki]

@davidcockey

Only planar curves have an associated “curve plane”. Non-planar curves do not have an associated “curve plane”.

Yes. This is obvious.

@davidcockey

If the construction plane is not normal to the curve a perpendicular line can be drawn in a plane parallel to the construction plane.

This is what I meant. I did not try to be precise.

@davidcockey

This is the current behavior.

Certainly not!

Here is precise definition of the new feature:

1. If the curve is planar, and the Line>Perpendicular command is used without the FromFirstPoint option, and perspective viewport is active, the line is drawn in the curve plane.
2. If the curve is planar, and the Line>Perpendicular command is used without the FromFirstPoint option, and ortho viewport is active, the line is drawn in a plane parallel to the construction plane.

[davidcockey]

@andrew.nowicki

Here is precise definition of the new feature:

1. If the curve is planar, and the Line>Perpendicular command is used without the FromFirstPoint option, and perspective viewport is active, the line is drawn in the curve plane.
2. If the curve is planar, and the Line>Perpendicular command is used without the FromFirstPoint option, and ortho viewport is active, the line is drawn in a plane parallel to the construction plane.

So you want the command to function differently with planar curves than with non-planar curves. The original description of your “new feature” did not say it was only for planar curves.

This discussion may be more appropriate in the primary Serengeti category.

[andrew.nowicki]

@davidcockey

So you want the command to function differently with planar curves than with non-planar curves

This is good comment. We do not want to Byzantine rules because all good ideas are simple. Maybe the best way to handle this problem is to always draw the line in a plane parallel to the construction plane when the FromFirstPoint option is not used.

@davidcockey

This discussion may be more appropriate in the primary Serengeti category.

I would rather keep our half-baked ideas here. This whole thread (Rhino 6 documentation bugs) deserves new category: Documentation.

[KelvinC (Kelvin Cheng)]

I updated the descriptions of the Loose option. Hope it’s clear.

[KelvinC (Kelvin Cheng)]

@andrew.nowicki

1. If the curve is planar, and the Line>Perpendicular command is used without the FromFirstPoint option, and perspective viewport is active, the line is drawn in the curve plane.

Not true if the curve is planar, but not parallel to the active CPlane.

@andrew.nowicki

If the curve is planar, and the Line>Perpendicular command is used without the FromFirstPoint option, and ortho viewport is active, the line is drawn in a plane parallel to the construction plane

I don’t think parallel and perspective views make difference.

If you draw a line perpendicular to a curve and then set the CPlane perpendicular to the curve at the start of the line, you will notice the line is always on that plane.

Looks like you have the two conclusions because the Planar mode is on? If you don’t, the end point of the line will be on the active CPlane.

[andrew.nowicki]

Your documentation says: Polycurve segments offset individually and break apart in the result.

I made two polycurves: open and closed. Offset> Loose broke the open polycurve, but it did not brake the closed polycurve.

[KelvinC (Kelvin Cheng)]

@andrew.nowicki

but it did not brake the closed polycurve.

I guess because they are tangent segments.

[andrew.nowicki]

@KelvinC

I guess because they are tangent segments.

Yes, they are tangent.

[andrew.nowicki]

@KelvinC

Not true if the curve is planar, but not parallel to the active CPlane.

@KelvinC

I don’t think parallel and perspective views make difference.

I agree. I was not describing actual behavior of Rhino, but desired behavior of Rhino. I described a problem and its solution.

The problem is that if the Line>Perpendicular command is used without the FromFirstPoint option, Rhino draws the line in a direction that is almost random. The line is perpendicular to the curve, but it is rotated about the curve by seemingly random angle. The following screenshot depicts red curve and 20 blue lines perpendicular to the curve at the same point. The problem is that nobody knows which line Rhino will draw.

My favorite solution is new Rhino feature: if the Line>Perpendicular command is used without the FromFirstPoint option, Rhino draws the line in a plane that is parallel to the construction plane.

[Helvetosaur]

@KelvinC

I updated the descriptions of the Loose option. Hope it’s clear

Hi Kelvin,
Couple of issues:
No
Offsets a curve within the tolerance setting (typo)

The Corner and Tolerance Options are not used and will not be shown

The output curve will have the same parameter structure as the input curve

[andrew.nowicki]

Default keyboard shortcut assignments are documented in this file:
http://docs.mcneel.com.s3.amazonaws.com/rhino/6/help/en-us/user_interface/shortcuts.htm

The file says: F7 Grid > ShowGrid > ShowGridAxes
It should say: F7 Grid > ShowGrid
…because F7 toggles visibility of the entire grid, rather than its axes.

[KelvinC (Kelvin Cheng)]

@andrew.nowicki

The problem is that if the Line>Perpendicular command is used without the FromFirstPoint option, Rhino draws the line in a direction that is almost random. The line is perpendicular to the curve, but it is rotated about the curve by seemingly random angle. The following screenshot depicts red curve and 20 blue lines perpendicular to the curve at the same point. The problem is that nobody knows which line Rhino will draw.

Use the Perpendicular and FromFirstPoint options in 2D space (planar curves on a CPlane), you will find they work as expected.

@andrew.nowicki

My favorite solution is new Rhino feature: if the Line>Perpendicular command is used without the FromFirstPoint option, Rhino draws the line in a plane that is parallel to the construction plane.

Turn on the Planar mode to achieve this.

[KelvinC (Kelvin Cheng)]

@Helvetosaur

Offsets a curve within the tolerance setting (typo)

Spell checking does not work in my editor.

@Helvetosaur

The Corner and Tolerance Options are not used and will not be shown

The output curve will have the same parameter structure as the input curve

English is not my native language. I use Grammarly to check my writing. When I use “will” it tells me…

When I use “be + past participle”, it tells me…

to make sentences less wordy and increase readability.

I changed the sentences as you suggested. Thanks.

[KelvinC (Kelvin Cheng)]

@andrew.nowicki

Yes, they are tangent.

I changed the description to…

Polycurve segments offset individually. Segments will break apart at corners in the result.

[KelvinC (Kelvin Cheng)]

@andrew.nowicki

The file says: F7 Grid > ShowGrid > ShowGridAxes
It should say: F7 Grid > ShowGrid
…because F7 toggles visibility of the entire grid, rather than its axes.

No, ShowGrid and ShowGridAxes can be toggled separately.
F7 Grid > ShowGrid will only toggle the grid lines.

[Helvetosaur]

@KelvinC

I use Grammarly to check my writing.

OK, if you need to follow the strict rules of tech writing that Grammarly wants, I guess you could say:

The Corner and Tolerance Options are not used and are not shown
The output curve has the same parameter structure as the input curve

[andrew.nowicki]

@KelvinC

Spell checking does not work in my editor.

I use Tinyspell spelling program. It works well with all editors and is free of charge. You can download it from: www.tinyspell.com/

@KelvinC

English is not my native language.

I have the same problem - my mother tongue is Polish.

[andrew.nowicki]

@KelvinC

No, ShowGrid and ShowGridAxes can be toggled separately.
F7 Grid > ShowGrid will only toggle the grid lines.

You are correct - F7 toggles both grid lines and grid axes.

[andrew.nowicki]

@KelvinC

Use the Perpendicular and FromFirstPoint options in 2D space (planar curves on a CPlane), you will find they work as expected.

When I draw the perpendicular line in ortho viewport, the line is not parallel to the construction plane.

@KelvinC

Turn on the Planar mode to achieve this.

Yes, the planar mode works in all viewports, but novice Rhino users may not know that the planar mode is necessary to control direction of the perpendicular line.