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

[jolran]

He he. This is bothering me badly. Most annoying.
One of my first ideas when I thought about this plugin was to let the user select from a scroll list, Front, Right, Left Back view etc, and have determined pt from bounds according to selection. That of course is not a flexible and smart solution. But maybe viable? Will be troublesome for in between angles.. It's not a good solution...

@unknownuser said:

relative to the vector formed by the face's first edge

Oh, yeah that's right

@unknownuser said:

A consistent and simple way would be to make it relative the the X-axis that has been transformed to lie on the face.plane ???

Do you mean create edge first on X and move to face.plane?

Or maybe select a reference edge as Sergey idea?

[jolran]

Hmm, no? I must have gotten it wrong. Doesent work in Y,Z axis.

[jolran]

Genious TIG!

I think I got it right. It work for me in a few tests.

Like this, no?

pt=face.vertices[0].position
      p1=pt.clone
      p1.x=p1.x+1
      p1=p1.project_to_plane(face.plane)
      ve=pt.vector_to(p1)
      bb=face.bounds
      di=bb.diagonal
      po=pt.clone

I mean is that correct for an update, cause this problem is(was) irritating.

[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.