Adding geometry to model - speed issues

thomthom

I don't think I've tested this on SU7 but on SU6, using the add_faces_from_mesh method was way faster than adding individual faces using the add_face method. I thought it was 3-4 times faster (but I don't remember for sure). Maybe they have tightened the gap between these method in SU7.1?

For a quick test, just use SDS. Normal operation using the add_faces_from_mesh method, but if you choose the 'copy materials' option, it uses the add_face method.

Yes - I find add_faces_from_mesh to be faster than add_face to be faster as well. But comparing the number of polygons in the mesh with the time it takes to add the geometry - time does not increase linearly. It does seem that the time relates to the number of entities already in the context you add to.

AdamB

@jim said:

@tig said:

GC.start is Jim's baby - built-in - As I understand it you start if before making the groups ?

I thought I learned of it on this forum!

I don't think it's the GC that's slowing adding geometry - more likely it is Sketchup looking to make faces and break overlapping geometry as geometry is either added or exploded. (pure conjecture.)

Try this:

` def addfaces(ents = Sketchup.active_model.entities)

vertices = [Geom::Point3d.new(0,0,0), Geom::Point3d.new(1,0,0),Geom::Point3d.new(0,1,0)]

start = Time.new
1000.times do
	ents.add_face vertices	
end
puts "Same tris took #{(Time.new - start)}"

start = Time.new
1000.times do
	ents.add_face vertices
	vertices[0].z += 0.1
	vertices[1].z += 0.1
	vertices[2].z += 0.1
end
puts "different tris took #{(Time.new - start)}"


start = Time.new
1000.times do
	ents.add_face vertices
	vertices[0].z += 0.1
	vertices[1].z += 0.1
	vertices[2].z += 0.1
end
puts "more different tris took #{(Time.new - start)}"

end

addfaces`

Firstly adds 1000 triangles using the same coordinates, secondly adds 1000 triangles with unique vertices, lastly adds another 1000 triangles with unique vertices. Shows a 10x difference in performance, yet the geometry engine will be constructing the topology in all cases - ie doing work.

This would seem to indicate its an insertion bottleneck - which is consistent with thomthom findings.

What does it mean? It means its a brick wall and adding geometry in SU is slow and there is nothing you can do about it.

thomthom

@adamb said:

What does it mean? It means its a brick wall and adding geometry in SU is slow and there is nothing you can do about it.

thomthom

I ran that script four times:

` addfaces
Same tris took 0.05
different tris took 0.71
more different tris took 1.9
nil

addfaces
Same tris took 1.84
different tris took 1.68
more different tris took 1.87
nil

addfaces
Same tris took 1.85
different tris took 1.659
more different tris took 1.89
nil

addfaces
Same tris took 1.85
different tris took 1.69
more different tris took 1.86
nil`

Didn't delete geometry in between.

thomthom

Moved the geometry slightly away from original position and ran three more tests:

` addfaces
Same tris took 1.8
different tris took 2.64
more different tris took 4.13
nil

addfaces
Same tris took 3.62
different tris took 3.26
more different tris took 3.65
nil

addfaces
Same tris took 3.62
different tris took 3.26
more different tris took 3.68
nil`

TIG

How about entities.fill_from_mesh(...) rather than add_faces_from_mesh(..)
http://code.google.com/apis/sketchup/docs/ourdoc/entities.html#fill_from_mesh
is that quicker ?

thomthom

I had a mad hope that Sketchup.break_edges = false might change something...

` Sketchup.break_edges=false
false

addfaces
Same tris took 3.58
different tris took 5.62
more different tris took 7.56
nil

Sketchup.break_edges=true
true`

nope!

@tig said:

How about entities.fill_from_mesh(...) rather than add_faces_from_mesh(..)
http://code.google.com/apis/sketchup/docs/ourdoc/entities.html#fill_from_mesh
is that quicker ?

oooh. I've missed that method. Will give it a wirl when I get home. That even has a number of features which saves me some work when it comes to smooth vs faceted.

Jim

@whaat said:

I wasn't aware of this method! Has it really been available since SU6??

Me either. I thought I knew the API up and down (I act like, sometimes!) Makes me wonder what else is in there.

edit - maybe it was always "there", just not documented until the new automatic document system started?

Whaat

@tig said:

How about entities.fill_from_mesh(...) rather than add_faces_from_mesh(..)
http://code.google.com/apis/sketchup/docs/ourdoc/entities.html#fill_from_mesh
is that quicker ?

I wasn't aware of this method! Has it really been available since SU6??
Someone, please do a performance test of this method now! (I would if I could.... )

thomthom

@whaat said:

@tig said:

How about entities.fill_from_mesh(...) rather than add_faces_from_mesh(..)
http://code.google.com/apis/sketchup/docs/ourdoc/entities.html#fill_from_mesh
is that quicker ?

I wasn't aware of this method! Has it really been available since SU6??
Someone, please do a performance test of this method now! (I would if I could.... )

I tried it in SU6 - it's there al'right. I will try in SU5 later today.

I think I've overlooked it because I've never used PolygonMeshes before.

thomthom

The old documentation doesn't seem to mention it: http://download.sketchup.com/OnlineDoc/gsu6_ruby/Docs/ruby-entities.html

Maybe it was added in the November update of the docs.

Whaat

@thomthom said:

The old documentation doesn't seem to mention it: http://download.sketchup.com/OnlineDoc/gsu6_ruby/Docs/ruby-entities.html

Maybe it was added in the November update of the docs.

Sometimes I just want to slap whoever was responsible for the API docs...however, right now, I want to kick them in the junk.

thomthom

Come to think of it - I do remember reading somewhere about PolygonMesh'es being added without error control and being somewhat quicker. But since I previously had no interests in PolygonMeshes I didn't pay much attention. Assumed there was only one method to add a mesh.

thomthom

fill_from_mesh exists in SU5 as well.

thomthom

fill_from_mesh seems to be twice as fast as add_faces_from_mesh.
But its default values doesn't match with the manual. The manual claims that the default for smooth is 0. But when I omit that value I get a soft and smooth mesh. I have to explicitly set it to 0 for no smoothing.

And I can't make out what the weld vertices do. I don't see any difference in what it produces.

thomthom

I might have been a bit quick to judge the speed difference...

Whaat

@thomthom said:

And I can't make out what the weld vertices do. I don't see any difference in what it produces.

Any performance increase when welding vertices?

thomthom

hm.. haven't tried too much with that right now. But I'm profiling a plugins right now. Might touch upon it later.

add_faces_from_mesh(polygonmesh)
` TT_Teapot.create_teapot(16)

Mesh generated in 11.35 seconds
Teapot with 16 segments generated in 13.201 seconds
#Sketchup::Group:0xe9c9268`

fill_from_mesh(polygonmesh)
` TT_Teapot.create_teapot(16)

Mesh generated in 0.157 seconds
Teapot with 16 segments generated in 2.02 seconds
#Sketchup::Group:0xe792a48`

thomthom

I find no noticeable difference in speed when I change smoothing and/or welding.
And I still have no idea what welding vs not welding really do.

thomthom

polygonmesh.point_index(point) is slow

Found it faster to build a separate Hash to keep track of it as I added the points for the mesh.

While adding points
point_index = {} p.each { |i| point_index[i] = pm.add_point(i) }

When collecting points to build polygon:
indexes = points.collect { |point| point_index[point] }