Best Strategy for Clean Geometry

MartinRinehart

I have a box method that Rectangles from one corner to a second corner, then PushPulls the rectangle to create a box. It works well if it doesn't mingle with other geometry. I want a nice, clean box not touching other geometry so I can group or component it, then let it go play with the other geometry. So far I've thought of

a) Push the current model onto a stack. File/New. Draw box. Save. Pop model. Import. (Can you File/Import in Ruby?)

b) Same as a) but use fresh layer, not model. Group/Component before moving to existing layer.

c) Code my own PushPull so I can keep references to rectangle's face and edges and all eight new edges and 5 new faces.

TIG

Why not group it first ?


group=model.active.entities.add_group()
group.entities.add_edges(...)
### etc
### Why wait till afterwards to group it ?
### You can always explode at at the end !

This also lets you find faces, edges etc more easily...

MartinRinehart

@tig said:

Why not group it first ?


> group=model.active.entities.add_group()
> group.entities.add_edges(...)
> ...
>

This also lets you find faces, edges etc more easily...

The implication is abandoning face.pushpull in favor of writing my own pushpull?

Be careful how you advise me, TIG. I have enough respect for you to actually take your advice.

TIG

Separating your new geometry inside a new group's entities [or component definitions entities] and then pushpulling it [or whatever you want to do to it] inside the group quite safely, and away from other geometry clashes is a good [English understatement for 'the correct'] way to make new stuff like this.

When you are done then you can explode the group and the geometry can intermingle with other stuff, if desired...

Personally I prefer to leave my new geometry grouped for the user to decide on the explode - see ExtrudeEdgesByRails et al...

MartinRinehart

@tig said:

Personally I prefer to leave my new geometry grouped for the user to decide on the explode


# /r/t.rb

# Work in progress. Do not put into service. 
# Finished version will be in my tutorial, Chapter 14.

def pp_add( pt, vec )
    return [ pt[0]+vec[0], pt[1]+vec[1], pt[2]+vec[2] ]
end 

def pp( face, distance )

    # the full vector is the face's normal times the pushpull distance
    norm = face.normal.to_a()
    vec = [ norm[0]*distance, norm[1]*distance, norm[2]*distance ]
    
    # create a new set of vertices 'vec' away from the original
    vs = face.vertices()
    new_vs = []
    
    for i in 0..vs.length-1
        new_vs[i] = pp_add( vs[i].position, vec )
    end
    
    # TIG's idea;
    ents1 = Sketchup.active_model.entities
    grp = ents1.add_group()
    inst = grp.to_component()
    defi = inst.definition()
    ents2 = defi.entities()
    a = []
    for v in face.vertices 
        a.push( v.position )
    end
    old_face = ents2.add_face( a )
    ents1.erase_entities( face )

    # add a face with the new vertices
    new_face = ents2.add_face( new_vs )
    
    # draw faces around the outside
    for i in 0..(vs.length-1)
        f = ents2.add_face( 
            new_vs[ i%vs.length ],
            new_vs[ (i+1)%vs.length ],
            vs[ (i+1)%vs.length ], 
            vs[ i % vs.length ]
        )
        f.reverse! if distance < 0
    end # loop over vertices
    
    # flip a face so they all face outside
    new_face.reverse! if distance < 0
    old_face.reverse! if distance > 0
    
    return inst
    
end # of pp()

Jim

I'm not understanding. This draws a box within the context of a Group.


pts = [ [0, 0], [0, 10], [10, 10], [10, 0] ]
group = Sketchup.active_model.entities.add_group()
face = group.entities.add_face(pts)
face.pushpull(10)

TIG

Martin is/was making it far too complex... it even converted the group to a pointless component ?
KISS...
Jim's example is the better way to do it... Explode the group at the end if desired...