Mesh

Functions for working with CINEMA 4D’s point and polygon objects.

TogglePolySelection(obj)

SelectAllPolys(obj)

SelectPolys(li, obj, clearOldSel=True)

Switch the selection state to ‘selected’ for a list of polygons. Expects a list of polygon indices.

If clearOldSel is True, clears the old polygon selection. Otherwise appends to the current selection. Default is True.

Returns:True if the selection state was changed, or False if obj is not a c4d.PolygonObject.

SelectPoints(li, obj, clearOldSel=True)

Switch the selection state to ‘selected’ for a list of points. Expects a list of point indices.

If clearOldSel is True, clears the old polygon selection. Otherwise appends to the current selection. Default is True.

Returns:True if the selection state was changed, or False if obj is not a c4d.PointObject.

GetSelectedPoints(obj)

Returns list of selected point indices.

To get the actual point(s), using an index from the returned list do something like

allpoints = op.GetAllPoints()
point = allpoints[index]

GetSelectedPolys(obj)

Returns list of selected polygons indices.

To get the actual polygon(s), using an index from the returned list do something like

allpolys = obj.GetAllPolygons()
poly = allpolys[index]

GetPointsForIndices(li, obj)

Return a list with the actual points from a list of point indices.

If li already is of type list<c4d.Vector> return the list untouched.

GetPolysForIndices(li, obj)

Return a list with the actual polygons from a list of polygon indices.

If li already is of type list<c4d.CPolygon> return the list untouched.

GetIndicesForPoints(lp, obj)

Return a list of point indices for all points that are equal to the vectors from lp.

Warning: can be time consuming for large models, since this has to check against all points each time for every element in lp.

You are better off acquiring the list of indices another way. Especially if it is just about converting a list of selected points to their indices.

Use GetSelectedPoints() in that case.

If lp already is of type list<int> return the list untouched.

GetPolysForPoints(li, obj, strict=True, threshold=3)

Returns a list of polygon indices for all polygons that have points with point indices given by li as their members.

This is the same as converting between selections by holding Cmd/Ctrl when pressing the modelling mode buttons in CINEMA 4D.

Parameters:

• strict (bool) – if True, return only those polygons that are fully enclosed by all the points that make up that polygon.
• threshold (int) – minimum number of points that must be shared to for strict mode to be considered as enclosing a polygon. 3 includes triangles, 4 would only include quads.

If li already is of type list<c4d.CPolygon> return the list untouched.

CalcPolyCentroid(e, obj)

Calculate the centroid of a polygon by averaging its vertices.

Parameters:e – can be c4d.CPolygon, list<int> representing point indices, or list<c4d.Vector> representing a list of points.

CalcPolyNormal(e, obj)

Calculate the orientation of face normal using Newell’s method.

See CalcVertexNormal() for an example of usage within the calling context.

Parameters:e – can be c4d.CPolygon, list<int> representing point indices, or list<c4d.Vector> representing a list of points.

CalcVertexNormal(v, idx, obj)

Calculate the vertex normal by averaging surrounding face normals.

Usually called from a construct like the following:

# calculate average vertex normal for point selection
vtx_normals = []

for i, point in enumerate(obj.GetAllPoints()):
    if pointsel.IsSelected(i):
        vn = CalcVertexNormal(point, i, obj)
        vtx_normals.append(vn)

N = VAvg(vtx_normals)

CalcAverageVertexNormal(obj)

Calculate the average normal of a selection of points.

This gives the same normal as setting the modelling tool to “Normal” mode for an arbitrary point selection.

Returns:normal, or zero vector if no points selected.

CalcThreePointNormal(a, b, c)

Calculate the surface normal of a three point plane.

Doesn’t take orientation of neighboring polygons into account.

CalcTriangleArea(p, obj)

Calculate area of a triangle using |(v3 - v1) x (v3 - v2)|/2.

CalcPolyArea(p, obj, normalized=False)

Calculate the area of a planar polygon.

CalcBBox(e, selOnly=False, obj=None)

Construct a BBox for a c4d.PointObject, a c4d.CPolygon, or a list of polygon indices. If you have a list of point indices you can construct a BBox directly using the FromPointList() class method.

You must supply the object the polygon list belongs to in the latter case.

Note that if you are interested in the midpoint or radius only, you can use the built-in c4d.BaseObject.GetMp() and GetRad() methods respectively.

Parameters:selOnly (bool) – if True, use selected points only if e is a c4d.PointObject. Otherwise use all points of the object.

CalcGravityCenter(obj)

Calculate the center of gravity for obj.

PolyToList(p)

Convert a c4d.CPolygon to a list of c4d.Vectors, representing the points of the polygon.

PolyToListList(p, obj)

Convert a c4d.CPolygon to a list<list> structure.

list<list> represents a list of points comprised of a list of coordinate values.

ListToPoly(li)

Convert a list of int representing indices into an object’s point list to a c4d.CPolygon.

ListListToPoly(lli)

Convert a list<list> structure to c4d.CPolygon.

list<list> represents a list of indices that indentify points of an object.