I have been playing with the new NURBS functionality in the BOSL2 library.
I've set up a parametric model that builds hollow pipes that are generated
from sweeping the evaluated points along the NURBS.  The complete part will
have many dozens of pipes, and when I take the differences between them to
form hollow pipeworks, I get the following error:

"WARNING: Normalized tree is growing past 200000 elements. Aborting
normalization."

Is there any documentation on how to reduce the normalization tree?

As a note, I already bumped up the turn-off rendering at "1,000,000" as
suggested by https://github.com/openscad/openscad/issues/3504  but I will
need to add a lot more to the model than what I have right now, and I am
not sure my computer can take 10 million rendering limit...

Also, this work is part of a collaboration, and I cannot share the full
code yet.  If people need I will mock up a simplified example to work on.
But that will probably take a far bit of work.  I was hoping someone has
done this type of cleanup before and has something written up.

Thanks and best regards,

EBo --

I am not 100% sure, but I don't think that this limit is related to the
number of points per se.  Rather, it is related to the number of CSG
nodes.  (It doesn't even seem to count operator nodes, just leaves.)

When you do a preview, watch the "Normalized tree has N elements!"
message in the console.  It's third from the bottom in mine, right after
"Compiling design (CSG Products normalization)...".

Are you generating tons and tons of tiny objects, like building
something out of a zillion individual cubes?

Design / Display CSG Products may be helpful.

Yeah, stroke() will end up making roughly two nodes (I think) per path vertex. Use path_sweep() instead.

-Revar

On Feb 28, 2025, at 6:19 PM, John David via Discuss <discuss@lists.openscad.org> wrote:

<face_palm> I was looking at the wrong code. This code uses the "stroke" module from BOSL2. I really need to clean up this code. Sorry for the noise...

On Fri, Feb 28, 2025 at 9:15 PM John David <ebo.2112@gmail.com> wrote:

I was using the "sweep" function from the Naca_sweep.scad library. This is older code I was playing with along the way. I think I should see if I can refactor it to use BOSL2's path_sweep function. They probably do the same thing. Thanks for the pointer!

On Fri, Feb 28, 2025 at 9:09 PM Jordan Brown <openscad@jordan.maileater.net> wrote:

On 2/28/2025 5:52 PM, John David wrote:

I'm currently getting "Normalized tree has 1936 elements!" At the moment, there are 9 intersecting hollow pipes. 7 of these pipes are generated from a NURBS that curve. When it generates the evaluation points it creates a lot of them, and then I sweep along this general path.

I've never used the NURBS stuff, but it looks purely mathematical; it doesn't look like it generates any geometry on its own.

When you say that you "sweep" along this path, exactly what do you mean?

Do you mean something like BOSL2's path_sweep(), or something else?

path_sweep() generates one node, so this is one node:

include <BOSL2/std.scad>
include <BOSL2/nurbs.scad>
$fs = 0.5;
$fa = 2;
control = [[5,0],[0,20],[33,43],[37,88],[60,62],[44,22],[77,44],[79,22],[44,3],[22,7]];
curve = nurbs_curve(control,2,splinesteps=16);
path_sweep(circle(2), curve);

<xB2hFqenzKHDI2iy.png>

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