Help please. How to get transformation for the face

[cesaro36]

Hi everyone
I need help to get the transformation of the current face under the cursor.
I'm using the input point method but my problem emerges when the cursor is Inferenced.

It is weird because my @ip.face is correct but @ip.transformation doesnt match.

I dont use a pick helper because I need to get faces outside p.e. when editing inside a component.

The only plugin that I've seen it managing well is AngleInpector from Freddo tools.

Any ideas?

Thanks

[sdmitch]

@ip.transformation would be the transformation of the parent of the face not the face itself.

[cesaro36]

thanks, but... what I mean is how to get the correct transformation for the face bellow when the cursor is inferenced. Is there something I'm missing?

[TIG]

A face doesn't have a "transformation" per se.
The "input point" your identify can give the transformation of where it was picked - which you can then use to modify entities' transformations later...
You can "transform" a group/instance, face, edge or vertex...

You can gather various info about any picked vertex/edge/face [e.g. position/line/center/normal ] - and devise transformations to modify these [bearing in mind the parent's transformation you have also collected...]
BUT what do you want to do ?

Please explain what you want to 'find' and what you want to do with it...

[cesaro36]

Thanks TIG
My intention is to highlight the face that the cursor is passing over.
In the Animation GIF you can see that when the interfering is happening the highlighted face is been drawn where it should'n, meaning that the transformation given by @ip.transformation is not the same as it was before the iterferencing while the @ip.face is still the same. (is that make sense)
I'm doing my best trying to explain this in english.

[Dan Rathbun]

Thanks TIG
My intention is to highlight the face that the cursor is passing over.

You can do this easily by pushing the face's reference into the model selection set.

old_set = model.selection.to_a
model.selection.clear
model.selection.add(@ip.face)

[Anton_S]

cesaro36,

Like TIG and others mentioned a face doesn't have a transformation, but its point positions are bound to the transformation of a group/component instance containing the face. In that case, you will need to transform all points of the face into global space before highlighting the face.

Here is a sample face highligher tool:

Code: Select all

class FaceHighlighterTool

  def initialize
    @ip = Sketchup::InputPoint.new
    @triplets = []
    @edge_points = []
    @hovered_face = nil
    @hovered_face_tra = nil
    @face_color = Sketchup::Color.new(0,40,255,80)
    @edge_color = Sketchup::Color.new(0,0,255,255)
    @edge_width = 3
  end

  def deactivate(view)
    @hovered_face = nil
    view.invalidate
  end

  def onMouseMove(flags, x, y, view)
    @ip.pick(view, x, y)
    face = @ip.face
    if face.nil?
      if @hovered_face
        @hovered_face = nil
        view.invalidate
      end
      return
    end
    if face != @hovered_face
      @hovered_face = face
      @hovered_face_tra = @ip.transformation
      # In order to draw a face with holes, we must draw its mesh
      mesh = face.mesh
      polygons_size = mesh.count_polygons
      @triplets = Array.new(polygons_size)
      for i in 0...polygons_size
        # Obtain one of the triangles making up the face
        triplet = mesh.polygon_points_at(i+1)
        # Transform to global space
        triplet.each { |pt| pt.transform!(@hovered_face_tra) }
        # Store for drawing
        @triplets[i] = triplet
      end
      # Get all edges for drawing a border
      @edge_points.clear
      face.edges.each { |edge|
        @edge_points << edge.start.position
        @edge_points << edge.end.position
      }
      # Transform all edge points to global space
      @edge_points.each { |point| point.transform!(@hovered_face_tra) }
      # Trigger the drawing
      view.invalidate
    end
  end

  def draw(view)
    return unless @hovered_face
    view.drawing_color = @face_color
    @triplets.each { |triplet|
      view.draw(GL_POLYGON, triplet)
    }
    view.drawing_color = @edge_color
    view.line_width = @edge_width
    view.line_stipple = ''
    view.draw(GL_LINES, @edge_points)
  end

end # class FaceHighlighterTool

Sketchup.active_model.select_tool(FaceHighlighterTool.new)

If you paste it all into Ruby Console you will see the effect.

Anton

[cesaro36]

Thanks Anton
I'll try it as soon as I get to my laptop.

[TBoy]

Anton_S,
Do you have similar code to highlight local bounding boxes (including those inside groups and components)?

[Anton_S]

There it is, TBoy:

Code: Select all

class BoundsHighlighterTool

  def initialize
    @ip = Sketchup::InputPoint.new
    @hovered_inst = nil
    @global_parent_tra = nil
    @global_bb = nil
    @labb_global_faces = [] # Faces for the local axes aligned bounding box.
    @gabb_global_faces = [] # Faces for the global axes aligned bounding box.
    @labb_global_edges = []
    @gabb_global_edges = []
    @labb_face_color = Sketchup::Color.new(255,40,0,80)
    @gabb_face_color = Sketchup::Color.new(0,40,255,80)
    @labb_edge_color = Sketchup::Color.new(255,0,0,255)
    @gabb_edge_color = Sketchup::Color.new(0,0,255,255)
    @edge_width = 3
  end

  def deactivate(view)
    reset(view)
  end

  def onMouseMove(flags, x, y, view)
    @ip.pick(view, x, y)
    ip_path = @ip.instance_path
    if ip_path.empty?
      reset(view)
      return
    end
    inst = nil
    gptra = nil
    ip_path.each { |ent|
      break if !ent.is_a?(Sketchup::Group) && !ent.is_a?(Sketchup::ComponentInstance)
      if gptra
        gptra = gptra * inst.transformation
      elsif inst
        gptra = inst.transformation
      end
      inst = ent
    }
    unless inst
      reset(view)
      return
    end
    return if inst == @hovered_inst
    @hovered_inst = inst
    @global_parent_tra = gptra
    local_bb = @hovered_inst.bounds
    # Obtain corners of local axes aligned bounding box in global space
    lagc = []
    for i in 0..7
      lagc << local_bb.corner(i)
    end
    if @global_parent_tra
      lagc.each { |point| point.transform!(@global_parent_tra) }
    end
    @labb_global_faces = [
      [lagc[0], lagc[2], lagc[3], lagc[1]],
      [lagc[4], lagc[6], lagc[7], lagc[5]],
      [lagc[1], lagc[0], lagc[4], lagc[5]],
      [lagc[2], lagc[3], lagc[7], lagc[6]],
      [lagc[0], lagc[2], lagc[6], lagc[4]],
      [lagc[3], lagc[1], lagc[5], lagc[7]]
    ]
    @labb_global_edges = [
      lagc[0], lagc[2],
      lagc[2], lagc[6],
      lagc[6], lagc[4],
      lagc[4], lagc[0],
      lagc[3], lagc[1],
      lagc[1], lagc[5],
      lagc[5], lagc[7],
      lagc[7], lagc[3],
      lagc[0], lagc[1],
      lagc[2], lagc[3],
      lagc[4], lagc[5],
      lagc[6], lagc[7]
    ]
    # Create global axes aligned bounding box
    @global_bb = Geom::BoundingBox.new()
    @global_bb.add(lagc)
    # Obtain corners of global axes aligned bounding box in global space
    gagc = []
    for i in 0..7
      gagc << @global_bb.corner(i)
    end
    @gabb_global_faces = [
      [gagc[0], gagc[2], gagc[3], gagc[1]],
      [gagc[4], gagc[6], gagc[7], gagc[5]],
      [gagc[1], gagc[0], gagc[4], gagc[5]],
      [gagc[2], gagc[3], gagc[7], gagc[6]],
      [gagc[0], gagc[2], gagc[6], gagc[4]],
      [gagc[3], gagc[1], gagc[5], gagc[7]]
    ]
    @gabb_global_edges = [
      gagc[0], gagc[2],
      gagc[2], gagc[6],
      gagc[6], gagc[4],
      gagc[4], gagc[0],
      gagc[3], gagc[1],
      gagc[1], gagc[5],
      gagc[5], gagc[7],
      gagc[7], gagc[3],
      gagc[0], gagc[1],
      gagc[2], gagc[3],
      gagc[4], gagc[5],
      gagc[6], gagc[7]
    ]
    view.invalidate
  end

  def draw(view)
    return unless @hovered_inst
    # Draw local axes aligned global bounding box
    view.drawing_color = @labb_face_color
    @labb_global_faces.each { |face|
      view.draw(GL_POLYGON, face)
    }
    view.drawing_color = @labb_edge_color
    view.line_width = @edge_width
    view.line_stipple = ''
    view.draw(GL_LINES, @labb_global_edges)
    # Draw global axes aligned global bounding box
    view.drawing_color = @gabb_face_color
    @gabb_global_faces.each { |face|
      view.draw(GL_POLYGON, face)
    }
    view.drawing_color = @gabb_edge_color
    view.line_width = @edge_width
    view.line_stipple = ''
    view.draw(GL_LINES, @gabb_global_edges)
  end

  def reset(view)
    return false unless @hovered_inst
    @hovered_inst = nil
    @global_parent_tra = nil
    @global_bb = nil
    @labb_global_faces.clear
    @gabb_global_faces.clear
    @labb_global_edges.clear
    @gabb_global_edges.clear
    view.invalidate
    return true
  end

end # class BoundsHighlighterTool

Sketchup.active_model.select_tool(BoundsHighlighterTool.new)

This time we iterate through the InputPoint's instance_path and transform the bounding box of the deepest instance across all the the parent groups/component instances in the path.