Help: Rhino.Geometry.HiddenLineDrawing.Compute viewport question

Hi @stevebaer or @GregArden
I am working on a script to automate some make2d stuff of blocks and I don’t understand how viewports work in this regard.

In ordinary Make2D we can choose Cplane and this is what I am after, but in Rhino Common it seems to me that I have to define what viewport to use, but the resulting geometry doesn’t end up in a predictable place. (if I move my camera a bit then the 2D lines moves to another location, and this just seems very strange to me, so I presume I do something wrong)

This is part of the code I am working on now cleaning up now (as a version 1.2 of what I have working)

Just make a block of a box or something with insertpoint = w(0,0,0), then use top view and run the script.
I would expect the 2D result to end up underneath the geometry of the block, but it ends up somewhere unpredicable. Now pan the view a bit and run the script again, now the result ends up somewhere else… Why is that?

import rhinoscriptsyntax as rs
import Rhino
import scriptcontext as sc

def make2D_of_objects(object_ids):
    tolerance_for_2d = 0.002
    # Get the active view
    rs.CurrentView("Top")
    view = sc.doc.Views.ActiveView
    viewport = view.ActiveViewport
    
    ###########################################################################
    # Process all of the objects
    ###########################################################################
    object_geometries = []
    for obj in object_ids:
        object_geometry = obj.Geometry
        # Check meshes and repair if it is
        if rs.IsMesh(object_geometry):
            object_geometry.Faces.RemoveZeroAreaFaces(0)
            object_geometry.Weld(0.0524) # = 35 degrees
        
        object_geometries.append(object_geometry)
    
    ###########################################################################
    # Create and define hidden line drawing parameters
    ###########################################################################
    parameters = Rhino.Geometry.HiddenLineDrawingParameters()
    parameters.AbsoluteTolerance = tolerance_for_2d
    parameters.Flatten = True
    parameters.IncludeHiddenCurves = False
    parameters.IncludeTangentEdges = False
    parameters.IncludeTangentSeams = False
    parameters.SetViewport(viewport)
    # Add geometry to parameters
    for object_geometry in object_geometries:
        parameters.AddGeometry(object_geometry, None)
    
    ###########################################################################
    # Create the hidden line drawing geometry
    ###########################################################################
    hld = Rhino.Geometry.HiddenLineDrawing.Compute(parameters, True)
    if not hld:
        return False
    
    ###########################################################################
    # Process the result
    ###########################################################################
    lines=[]
    for hld_curve in hld.Segments:
            if hld_curve.SegmentVisibility == Rhino.Geometry.HiddenLineDrawingSegment.Visibility.Visible: 
                # Copy the curve, transform and add to document
                curve = hld_curve.CurveGeometry.DuplicateCurve()
                if not curve.IsShort(0.01):
                    lines.append(curve)
        
    # Join curves
    joined_curves = Rhino.Geometry.Curve.JoinCurves(lines)
    result = []
    for joined_curve in joined_curves:
        result.append(sc.doc.Objects.AddCurve(joined_curve))
    if len(result) == 0:
        return False
    
    return result

object_id = rs.GetObject()
block_objects = rs.BlockObjects(rs.BlockInstanceName(object_id))

objects=[]
for object in block_objects:
    objects.append(sc.doc.Objects.Find(object))

#print objects

make2D_of_objects(objects)

PS! I found that HiddenLineDrawing really doesn’t like bad meshes, so I added a fix for that. It would be nice if the fix could be incorperated.

3 posts - 2 participants

Read full topic