working meanwhile...

thanks for the help.

But that part of the code:

if @woche.to_i >= start.to_i && @woche.to_i < ende.to_i #@woche variable of the class
    e.material = mats["im_bau"]
    e.back_material = mats["im_bau"] #why doesn't it work?
end
if @woche.to_i >= ende.to_i
    e.material =mats["fertig"]
    e.back_material =mats["fertig"]  #why doesn't it work?
end
if @woche.to_i < start.to_i
    e.material = mats["noch_nicht_angefangen"]
    e.back_material = mats["noch_nicht_angefangen"]  #why doesn't it work?
end

should have been working, shouldn't it?
I don't understand why the materials were assigned to the front, but not to the back of the face.
any idea?

Hallo!

I am going to set the material of a face in the following method. To avoid problems with the oriatation of the face's normal I want to set its back_material, too.
I tried it with the following code:

def status_anzeigen #funktioniert, nur das mit dem alpha wert im material inplanung noch nicht so
  mod = Sketchup.active_model
  ents = mod.entities 
  sel = mod.selection 
  mats = mod.materials
  bau_mat = mats.add "im_bau" if not bau_mat = mats["im_bau"]
  bau_mat.color = [255,127,38] 
  fertig_mat = mats.add "fertig" if not fertig_mat =mats["fertig"]
  fertig_mat.color = [211,211,211] 
  inplanung = mats.add"noch_nicht_angefangen" if not inplanung = mats["noch_nicht_angefangen"]
  inplanung.color = [176,196,222] 
  inplanung.alpha = 0.3 

  ents.each{|e|
            if e.typename == "Face"
                 start = e.get_attribute "ablauf", "baubeginn"  #attributes that were assigned to the faces before
                 ende = e.get_attribute "ablauf", "bauende"     #attributes that were assigned to the faces before
                 
                if (e.material) #checking wehther the faces current material belongs to the ones created at the top of the method, if not, save the name of the current material as an attribut
             
                   invalid_materials = ["im_bau", "fertig", "noch_nicht_angefangen"]
                   unless invalid_materials.include?( e.material.name )
                     mat_vorher = e.material.name
                     e.set_attribute("ablauf", "material", mat_vorher)
                   end
                 end
                 
                 
                 if @woche.to_i >= start.to_i && @woche.to_i < ende.to_i #@woche variable of the class
                   e.material = mats["im_bau"]
				   e.back_material = mats["im_bau"] #why doesn't it work?
                 end
                 if @woche.to_i >= ende.to_i 
                   e.material =mats["fertig"]
				   e.back_material =mats["fertig"]  #why doesn't it work?
                 end
                 if @woche.to_i < start.to_i 
                   e.material = mats["noch_nicht_angefangen"]
				   e.back_material = mats["noch_nicht_angefangen"]  #why doesn't it work?
                 end
            end
                 
           }
end

Only the "front" of the face was changed to the new material. Does anybody know what mistake I made?
Thanks for your time.
Tim

Great!
Thank you.

Hallo!

How is it possible to hide and unhide an entity?

Thanks for your time.

I study civil engineering and the script is some kind of homework. I'll talk to my tutor in two days. After that I'll know wether I'm allowed to give you the code.
Thanks so far.
Tim

Step by step what I want to do:

1. a scribt assigns information to selected faces of the model as attributes.
2. another one creates a bar chart (the entities that should be erased later) based on the attributes of the faces on a layer called "balkenlayer".
3. a selection observer is used to go back to the model to go on working on it. that observer should delete the bar chart (everything on the layer "balkenlayer").
4. later it schould be possible to invoke the script that created the bar chart once more.

it is working so far. in the 3. step every entity on that layer seems to be erased. but if i invoke the scribt once more as mentioned in step 4, sketchup tells me:

"your recent operation has caused visible geometry to merge with existing geometry on a hidden layer"

although the is nothing to see.
do know now what i am trying to receive?
is there maybe an array that stores the entity although it got erased or something like that?

thank you guys for your time.

The geometry isn't disconected. I wrote a scribt that should display some information, that is saved as an attribute of the faces, in a diagramm an text on a different layer ("balkenlayer"). Then it should be possible to go on working on the model and to invoke the scribt that shows the information on "balkenlayer" again. So far the diagramm and the text is displayed on the layer and the geometry of it seems to be erased. But when I invoke the scribt one more time, Sketchup still tells me, that:

"your recent operation has caused visible geometry to merge with existing geometry on a hidden layer"

Although I meanwhile use the following code:

layer = layer_array["Balkenlayer"]
	  return nil if not layer
	  mod.entities.to_a.each{|e| next if not e.valid?; e.erase! if e.layer==layer}

I don't understand why.Though there is no geometry to see if only the "Balkenlayer" is visible.
Any idea?

But isn't that exactly the code I already used?

Hallo!

I wrote a scribt that creates some entity objects on a layer called "Balkenlayer". Now I try to write a scribt that deletes every entity object on "Balkenlayer" to be able to execute the first scribt I wrote more then only one time without having the entity objects created by the first invoking of the scribt on the layer.

As adviced I used

mod = Sketchup.active_model
mod.active_entities.to_a.each{|e| next if not e.valid?; e.erase! if e.layer==layer_array["Balkenlayer"] }

to delete the objects on Balkenlayer. But every time I invoke the first scribt that created the objects on "Balkenlayer" after the should have been deleted, Sketchup opens a window that tells me:
"your recent operation has caused visible geometry to merge with existing geometry on a hidden layer"

In the next step nothing happens.
Do you know what I have to change?
Thanks for your time.
Tim