Need Help With A VERY Model

[RocketNut 1]

Howdy 😊

 

I am using Cura 4.0 and have a really complex model that produces a very large  STL file, almost 1.4G. Here a link to the file (https://www.dropbox.com/s/pn4m8okhhl6sprq/NozzleMainRing.7z?dl=0). It takes a few minutes for Cura load it up. Sometimes it locks my machine up to the point I have to cycle the power switch. When I get it to load the model it does not slice the model!!! Using task manager I see while loading memory usage goes up about 8G of memory. Then after a few mins (about 10Mins) the memory down to less then 500M.  There it sits with task manager reporting CPU usage less 1%. Which tells me the slicer is not running. I have let it run overnight, with the same results, the model was not sliced.

 

If anyone has any idea of what is going on please respond to post.

 

Thanks

Edited March 28, 2019 by RocketNut

[rowiac 53]

I don't know why exactly Cura is acting the way it is, but that for sure is a HUGE file.  Have you thought about decimating it using a tool such as MeshLab?  You probably wouldn't notice any detail loss, but you could significantly reduce the file size allowing Cura and your computer to handle it better.

[gr5 2,167]

You need to put out fewer triangles.  If you have this in cad, when you export to STL you should be able to lower the resolution by a factor of 10X and still have plenty of accuracy well beyone what most printers can do.  Or you can reduce the polygons using meshlab as rowiac suggests.  Here is a guide:

 

http://www.shapeways.com/tutorials/polygon_reduction_with_meshlab

 

I find that 100K polygons is usually enough for most models.  Certainly a million polygons should be more than enough for this model.

 

This model looks like much of it might be too thin to print.

[geert_2 557]

In the beginning when I started 3D-printing, my collegues of the department of Product Development suggested me to keep STL file-sizes below 20MB for normal models, even for their industrial polyjet printers.

 

If you are in doubt which quality of STL export-settings to use, then cut out a small part of this design, export it with various STL-settings, and print these little test pieces next to each other. So you can compare and find the best balance between file-size and quality.

 

[RocketNut 1]

Sorry for the delay in my responding back. I was called away from my desk.

 

There news of the STL size. A co-worker exported the model to an STL file by accident. The resulting file was below 450M!!! Cura now loads it fairly quickly, and it now slices the file with no trouble. According to Cura the model is 280 X 280 X  183.5 mm and will take 7 days to print!!

 

The only I can think of is my CAD program (AlibreI for some reason it did not export properly. Just strange.

 

 

rowiac:
I will check into MeshLab.

 

 

gr5:

 I have not yet read the tutorial, when I get some free time I will read. As for my CAD exporting to STL settings, here is a screen capture of it setting I have.

Also, the thin line has never been a problem in the past. For me, my CR-10 printer does an excellent no matter how thin the lines. Not to mention the great detail (no matter how small) it has shown.

 

 

geert_2:::

This is a model of a rocket nozzle. The model I am trying to print is 40% of real nozzle size. Because the nozzle has to be a single piece. so cutting to up smaller pieces is not an option. When it comes time to print an actual nozzle we will send it to a vendor who can print it full scale using graphite as the printing material.

 

===============================================

 

The other attached pic is a 3D rendering (KeyShot)  of the part.

 

Again thanks for all the help and suggestions 😄

Edited March 29, 2019 by RocketNut

[gr5 2,167]

1 degree for all those small circles is much more than necessary.  Most cad programs default to about 10 degrees (36 line segments in a circle).  But that might not be enough for your largest circles.

[geert_2 557]

@gr5: thanks for clarifying the degree-thing: although I knew the setting, I didn't know what it refered to in the physical world. I took a look in DesignSpark Mechanical, and indeed, it defaults to 10°, and 0.5mm max deviation for STL-export, in "Fine quality" settings.

 

See the picture below: the carabiner as designed, and as exported to STL (Fine quality, 10°, 0.5mm). For reference: the whole hook is 60mm long x 6mm high, and the text caps height of the watermark is 3.5mm, text legs are 0.5mm. The watermark is present but not visible in the STL-file: I made its color opaque to show the facets better.

 

So, for the rocket-engine, I would rather go a bit more accurate, maybe 5° or 2°? Unless the facets would be no functional problem.

 

 

 

 

[RocketNut 1]

OK I will try a larger circle degree. I also agree since this just an eng model then I don't need this low circle degree of modeling, just the actual part.does.

 

I will do a print of the model with a larger circle degree, I will let you know how this test print comes out.