Thank you, Dan, it works OK now!

Hello, can anyone explain to me why I get error msg.: ***Error: #<NameError: undefined local variable or method `field_build' for Visual::Plugin_A:Module>***on this code:

require("visual_visual_mod.rb")
require("sketchup.rb")

module Visual;;Plugin_A

# module methods, module vars, etc.

  unless file_loaded?(File.basename(__FILE__))
  
  Visual;;SUBMENU_VisDose.add_item ("VisDose 3D") {


field_build

}

def field_build


model=Sketchup.active_model
entities=model.active_entities
mod = Sketchup.active_model # Open model
entities = mod.entities # All entities in model
status = entities.clear! #clear current model



path = UI.openpanel "Open Data File", "d;\\", "*.txt"

 prompts = ["Alpha; "]
 defaults = ["0.5"]
 alpha = UI.inputbox prompts, defaults, "Please set transparency."


File.open(path).each_line {|line|

values=line.split(' ')

	x1=values[0].to_f
	y1=values[1].to_f
	z1=values[2].to_f
	color=values[3].to_f
	size=1

	x2=(x1+1)
	y2=(y1+1)



    pt1 = [x1, y1, z1]
    pt2 = [x2, y1, z1]
    pt3 = [x2, y2, z1]
    pt4 = [x1, y2, z1]


case color

	when 8..1000 then
		face1=entities.add_face pt1, pt2, pt3, pt4
		face1.material=[255,0,0]
		face1.material.alpha=alpha[0].to_f
		face1.back_material=[255,0,0]
		face1.back_material.alpha=alpha[0].to_f
		face1.pushpull size, true

	when 7..7.99 then
		face2=entities.add_face pt1, pt2, pt3, pt4
		face2.material=[255,86,25]
		face2.material.alpha=alpha[0].to_f
		face2.back_material=[255,86,25]
		face2.back_material.alpha=alpha[0].to_f
		face2.pushpull size, true

	when 6..6.99 then
		face3=entities.add_face pt1, pt2, pt3, pt4
		face3.material=[255,220,25]
		face3.material.alpha=alpha[0].to_f
		face3.back_material=[255,220,25]
		face3.back_material.alpha=alpha[0].to_f
		face3.pushpull size, true

	when 5..5.99 then
		face4=entities.add_face pt1, pt2, pt3, pt4
		face4.material=[254,254,76]
		face4.material.alpha=alpha[0].to_f
		face4.back_material=[254,254,76]
		face4.back_material.alpha=alpha[0].to_f
		face4.pushpull size, true

	when 4..4.99 then
		face5=entities.add_face pt1, pt2, pt3, pt4
		face5.material=[128,255,0]
		face5.material.alpha=alpha[0].to_f
		face5.back_material=[128,255,0]
		face5.back_material.alpha=alpha[0].to_f
		face5.pushpull size, true

	when 3..3.99 then
		face6=entities.add_face pt1, pt2, pt3, pt4
		face6.material=[0,255,0]
		face6.material.alpha=alpha[0].to_f
		face6.back_material=[0,255,0]
		face6.back_material.alpha=alpha[0].to_f
		face6.pushpull size, true

	when 2.5..2.99 then
		face7=entities.add_face pt1, pt2, pt3, pt4
		face7.material=[0,160,177]
		face7.material.alpha=alpha[0].to_f
		face7.back_material=[0,160,177]
		face7.back_material.alpha=alpha[0].to_f
		face7.pushpull size, true

	when 2..2.49 then
		face8=entities.add_face pt1, pt2, pt3, pt4
		face8.material=[0,86,255]
		face8.material.alpha=alpha[0].to_f
		face8.back_material=[0,86,255]
		face8.back_material.alpha=alpha[0].to_f
		face8.pushpull size, true

	when 0..2 then
		face9=entities.add_face pt1, pt2, pt3, pt4
		face9.material=[0,86,255]
		face9.material.alpha=alpha[0].to_f
		face9.back_material=[0,86,255]
		face9.back_material.alpha=alpha[0].to_f
		face9.pushpull size, true
	else

		face10=entities.add_face pt1, pt2, pt3, pt4
		face10.material=[0,0,255]
		face10.material.alpha=alpha[0].to_f
		face10.back_material=[0,0,255]
		face10.back_material.alpha=alpha[0].to_f
		face10.pushpull size, true

end


 
}
 styles = Sketchup.active_model.styles
 status = styles.add_style "D;\\xray.style", true


end

	
    file_loaded(File.basename(__FILE__))
	
end	
end

Thank's

Thank's to all, problem solved!

Hello Experts!

for study purposes I need to create a SketchUp Ruby script for volumetric visualization of radiation dose. Dose volume must be divided into voxels where each voxel have x;y;z coordinates and value V which represents dose intensity, besides the voxels must be colored in different colors regarding to value V. For example, if 5>V>3, then color = blue, but if 10>V>5, then color = green et cetera.
Can someone suggest a script to modify for my needs or help solve this problem?

P.S. I am not an IT professional, my field of study is physics, so scripting is not an ordinary activity for me

Thanks in advance,

Martins