[Plugin] Hatchfaces (v1.8 beta) UPDATED 15-Dec-2012

TIG

You need to trap for the case when the X-axis is parallel with the palne and then use another axis - i.e. offset the y instead of the x value of p1...
To do this get the n=face.normal and then use the alternative vector [offset in y] if n.x.abs==1 or n.z.abs==1
etc...

jolran

Hmm I will try..

Where do you learn all these commands?? It feels like I'm missing some information source(exept from this forum).

BTW won't there be a conflict of axes if one for ex. have a face rotated 45 degrees?

TIG

No.
The problem arises if you try to project a p1 onto a face with a plane that is square to the x-axis or flat to it, as that p1 is then back on p0 and the vector can't have a zero length!

jolran

@unknownuser said:

vector can't have a zero length!

That I can understand. Alright, I will have a go at it. I'm not sure a fully grasp this
This is more and more your plugin, it's starting to be too complicated for me. My level is more icons and stuff.
Maybe one day I can contribute more.

Thanks for your invaluable help TIG

kyyu

@jolran said:

Hmm I will try..

Where do you learn all these commands?? It feels like I'm missing some information source(exept from this forum).

You have to learn the ruby language itself. I'm lacking in this area, too.

jolran

@unknownuser said:

You have to learn the ruby language itself

Yeah, you are right. Working on that.

Good news is the code seams to be working for sorting irregular faces and hatching.


      p1=pt.clone
      p1.x=p1.x+1 # X value = x axis needs to be replaced if using another axis
      
      p1=p1.project_to_plane(face.plane)
      ve=pt.vector_to(p1)
      bb=face.bounds
      di

So something like this does not do the trick yet. Will work on it..

 p1.each {|e|e.z+1 if face.normal.z.abs==1
      e.x+1 if face.normal.x.abs==1
      e.y+1 if face.normal.y.abs==1}

TIG

Read this and try to understand...

p0=face.vertices[0].position
p1=p0.clone
if face.normal.x.abs>0.9999
  p1.y=p1.y+1
else
  p1.x=p1.x+1
end#if
p1=p1.project_to_plane(face.plane)
ve=p0.vector_to(p1)
### etc

This should always result in a 've'ctor with a non=zero length.
To test it set up a cube and test add temporary 'puts' into the code after ve=
puts face.normal puts ve.length

jolran

Wow, thanks! So if I understand it correctly one do only need to compare x to y to get the required results. Where if>0,9999 switches to other axis-comparison=under1? Clever.

It works for faces without holes if I switch values p0 to pt, with your last posted code.
Or do you mean p0 to be po, (typo)? Cause that is a whole different thing. That does not makes sence though, wonder why I think that...

I will try that meanwhile..Se if holes get fixed.

po=pt.clone:

ps=pt.offset(vp)
        pe=pt.offset(vp.reverse)
        gents.add_line(ps,pe)
        pt.offset!(vs,spacing)
        ps=po.offset(vp)
etc

jolran

Anyway heres how I implemented your code, between ents erase(facestogo) and intersection. It does not work on faces with holes, as mentioned.
Is there a clash with 2 pt.clones? Maybe I HAVE put your code in wrong places. I will continue..

bb=face.bounds
      di=bb.diagonal
       pt=face.vertices[0].position
        p1=pt.clone
     if face.normal.x.abs>0.9999
      p1.y=p1.y+1
     else
      p1.x=p1.x+1
     end#if
      p1=p1.project_to_plane(face.plane)
       ve=pt.vector_to(p1)
        po=pt.clone
      tr=Geom;;Transformation.rotation(pt,face.normal,@angle.degrees)
       vp=ve.transform(tr)
        vp.length=di*2
         vs=face.normal.cross(vp) #spacing vector perpendicular to hatch line
         tot=0
      until tot>=di*2
        ps=pt.offset(vp)
         pe=pt.offset(vp.reverse)
          gents.add_line(ps,pe)
           pt.offset!(vs,spacing)
            ps=po.offset(vp)
           pe=po.offset(vp.reverse)
          gents.add_line(ps,pe)
         po.offset!(vs.reverse,spacing)
        tot=

jolran

May have found something? Commented out the last parts. Line hatching and intersection.
The results of faces with holes is a group(clone) with reversed face? Faces without holes is created as expected.
Since using face.normal that might (in my theory logic) pose some trouble?

Updated Hmmm, no. Grr. Did not matter if faces was reversed or not. Problem remains..

This code reverses the faces anyway.
Could be useful later on, but it will reverse ALL faces, wich is not useful right now. Faces without holes do not need reversing.

faces2=[]
      gents.each{|e|faces2 << e.reverse! if e.class==Sketchup;;Face

TIG

Perhaps instead of pt=face.vertices[0].position it might be better to use pt=face.outer_loop.vertices[0].position

jolran

It does not work

However i noticed that "face" entity gets erased after erase(facestogo) if it has holes in it. Not if it's a square for ex!

I used puts face after loop face erasing..

So do face.plane have something to refere to when there are holes? Or is the variabel set earlier?

TIG

Erase the faces after you've set the points/vector etc - you can't get the plane or normal of an erased face!

jolran

AHA!!

So even if I am stupid enough to make that misstake, I noticed that in fact that was the error going on?

I'm making progress!!

Thanks TIG. I will try to fix it.

jolran

The "earliest" place where I can insert gents.erase_entities(faces2go) without erasing the access to face.plane is:

tr=Geom;;Transformation.rotation(pt,face.normal,@angle.degrees)
       vp=ve.transform(tr)
        vp.length=di*2
         vs=face.normal.cross(vp) #spacing vector perpendicular to hatch line
          gents.erase_entities(faces2go)

The result is not correct. Missing edges and too short.

Is face.plane or any command referring to "face" using the inner-hole faces, perhaps?
Should one use gents.entities.face(or something to retrieve the face.entity in gents) instead of just face?

TIG

You can set variables plane=face.plane and normal=face.normal and pt=face.outer_loop.vertices[0].position, then face.erase! - the variables are still remembered... then use them later as needed ?

jolran

@unknownuser said:

You can set variables plane=face.plane and normal=face.normal and pt=face.outer_loop.vertices[0].position, then face.erase!

Ok. You mean before faces2go << face? After erase.faces2goI was going to define the
linehatching as a method for crosshatching, as we discussed earlier. They will have to be instance.variables then or do I pass all of them into the argument-list when calling the method?
That's why I was wondering if one could use face from gents.entities, since gents will be passed into the args-list anyway.

Or did you originaly mean I should put the whole operation into a method for crosshatching?

I'm sorry if I sound confused. But I am.

TIG

All this part is trying to do is set the vector from which you will set the angle for the hatching.
At the moment it's set from the vertices [0] to [1] vector which varies, so to fix it I suggested a way of projecting the x-axis onto the face.plane and getting a vector from that to use instead [with changes for a plane that doesn't play nicely with the x-axis to give a valid vector...
You get all of this from the original face NOT the temporary face ??

jolran

@unknownuser said:

You get all of this from the original face NOT the temporary face!

Yes, that part I understand(hopefully) what it was about to fix for problems.

However when you said I can't get the plane or normal of an erased face, I thought
order matters. I think my english is a bit bad, I don't understand everything right away. Apologize for that.

Lets say I use ORIGINAL "face" for face plane, I still must pass "face" on in the argument-list if I am going to
have following script setup, wich will be needed for crosshatching later on, no?

Feels like I'm doing some fundamential misstake here.

(edited)It should be "face" in the argument list. NOT faces.

jolran

Think I got! @face=gents.add_face etc..in tha Face creating-part And use @ varibles in the code below seams to do the trick!
It works on holes anyway. Don't know how kosher that is TIG? It would get into the linehatching method.