About color

thomthom

Are you drawing into an empty context? Or into a context with existing geometry?

thomthom

If you draw into a context where it's only your group, you can do this:


entities.each { |e|
  next unless e.is_a?(Sketchup;;Face)
  e.material = 'blue'
}

If you are drawing into a context with existing geometry:


cache = entities.to_a
face = entities.add_face( [1, -1, 1], [1, 1, 1], [-1, 1, 1], [-1, -1, 1] )
face.pushpull(1)
(entities.to_a - cache).each { |e|
  next unless e.is_a?(Sketchup;;Face)
  e.material = 'blue'
}

AdamB

Nice thomthom, but wouldn't it be simpler to apply color to the face and then pushpull and it will pick up the material of the originating face.

thomthom

@adamb said:

Nice thomthom, but wouldn't it be simpler to apply color to the face and then pushpull and it will pick up the material of the originating face.

I did think of that - but when modelling I some times find PushPull to apply the material to the back-side of the extruded faces. Though not always - haven't worked out when it happens. (material is on the front face)

thomthom

Good pragmatic solution.

AdamB

Whoa there! Hammer to crack a nut there.

In a right handed system (like SU), the front of a Face is defined in an anti-clockwise direction. Imagine gripping the face normal with your right hand and your thumb in the direction of the normal - your fingers show the winding of the face.

Face#pushpull() takes a distance to move along the face normal. So if you define a Face and paint its front material with something, then apply a negative pushpull, you'll always get a cuboid with that material on the outside.

Adam

Dan Rathbun

@thomthom said:

@adamb said:

Nice thomthom, but wouldn't it be simpler to apply color to the face and then pushpull and it will pick up the material of the originating face.

I did think of that - but when modelling I some times find PushPull to apply the material to the back-side of the extruded faces. Though not always - haven't worked out when it happens. (material is on the front face)

But if you applied to both the front and back before push-pulling, then all will have the color afterward.

TIG

The loop 'direction' does indeed force the face.normal except in one important case... If you draw a 'flat' face a z=0 it will always face downwards no matter which 'direction' you might have drawn the loop :!

It's a quirk of Sketchup - it thinks you are going to PushPull the face 'up' in that case so it orients it for you to suit. It happens when making flat faces at z=0 both manually AND via the API.

Whenever I do this sort of face making I always check for
face.nornal.z==-1 and face.vertices[0].position.z==0
and if true and if I want to PushPull the face 'up' I add face.reverse! before I face.pushpull(distance). Remember too that you also use a negative distance to make the 'box' above an 'upwards looking' face...

Incidentally Adam is right that adding the material before doing the PushPull is the simplest way to make all of the new faces in that material. It is best to leave face-backs in the default 'blue' back-material as it's easier to see what's happening without resorting to Monochrome mode to check faces are correctly oriented...

Dan Rathbun

@adamb said:

Whoa there! Hammer to crack a nut there.

Well not a hammer (you overreact..) nut..

The problem does not occur with the built-in pullpull tool.

Does SU automatically reverse the face that is colored differently, using the built-in Tool?

EDIT: I guess TIG answered the nitty-gritty there. The API doesn't say that Face.pushpull's second argument defaults to false.

thomthom

@dan rathbun said:

@adamb said:

Whoa there! Hammer to crack a nut there.

Does SU automatically reverse the face that is colored differently, using the built-in Tool?

In my experience - yes, sometimes.

zps222

Thank you all guys