STL Import Problem

[kstrauss]

I'm trying to import a STL for a rotary job and getting strange artifacts. The STL looks fine in several STL viewers. What am I doing wrong?

I have attached the .CRV before I do the import. STL files cannot be added here so I renamed it as Mister75.stl.txt to allow it to be attached. You will have to rename it to Mister75.stl. The .CRV becomes huge after the import so I cannot attach it. All of the files can be accessed at https://1drv.ms/u/s!Ar5PqS2A2LDuicMtTMb ... g?e=BwnA4S

[sharkcutup]

Are you importing the model using the model menu or modeling tab?

If not try either one of those options!

That is one huge model 19.4409" in diameter and 38" long

Sharkcutup

[kstrauss]

I've tried importing both ways and the results appear to be identical. It is actually rather small at 0.76x1.5 inches (the STL was created in MM and I selected Model units under Model Scaling).

[sharkcutup]

Added a 3D roughing toolpath with .25 ballnose to your imorted .crv file and a 3D Finish Toolpath and it seems fine to me but then again I have never attempted a rotary file yet. But the Vectric simulation shows that is works fine as is. But what do I know I never have done rotary!!! There something is I noticed though after the roughing pass there is little material left at the ends (attach/hold) locations!!!

2D view of the model does look strange just have to remember this is what it looks like stretched out flat!

Sharkcutup

[sharkcutup]

Roughing Toolpath

Finish Toolpath

This is what I get after the above toolpaths!

Sharkcutup

[kstrauss]

Immediately after the import I get

Notice the banding along the side. I get essentially the same banding when I actually cut the job.

[mezalick]

In what program was the STL created?
Thanks
Michael

[sharkcutup]

This is a closeup preview image from VCarve Pro at preview Simulation Quality of Very High (4x Slower) using a .25 Radiused Ball Nose Router Bit with a 10% Stepover (.025").

I do not know what router bit you may be using but you may try various stepovers to see which is best.

This is what the model looks like when brought into VCarve Pro it does contain some banding (as you call it). But after adding the toolpaths I had noted in an earlier post it looks like the Simulation Preview noted above.

Sharkcutup

[TReischl]

There was a similar issue quite some time ago, maybe a year or so. Has to do with the number of triangles that are being output by the originating program. Not sure what the solution was, if any. IIRC adding lines in the design software helped. Not even sure what you would search for to see the discussion. . . .

[kstrauss]

Thanks for the clue regarding a previous discussion. After considerable searching I found viewtopic.php?f=2&t=32700&p=237448&hili ... em#p237448 which describes a problem very similar to mine.
Greg K wrote that:
"It seems that the current tolerance for this part of the importing process is not small enough, allowing visibly bend unwrapped triangles that produce the "bubbly" effect. The workaround is to attempt to produce an STL with more triangles than necessary as per TReischl's suggestion.
There will be a patch for the issue but it needs further testing."
This was posted over a year ago so I suppose that the further testing has not gone well!

[gregk]

Thanks for the clue regarding a previous discussion. After considerable searching I found viewtopic.php?f=2&t=32700&p=237448&hili ... em#p237448 which describes a problem very similar to mine.
Greg K wrote that:
"It seems that the current tolerance for this part of the importing process is not small enough, allowing visibly bend unwrapped triangles that produce the "bubbly" effect. The workaround is to attempt to produce an STL with more triangles than necessary as per TReischl's suggestion.
There will be a patch for the issue but it needs further testing."
This was posted over a year ago so I suppose that the further testing has not gone well!

The fix that I've mentioned was in fact included in V9.519. It does not eliminate the issue completely, but it reduces its severity:
Before V9.519:

After V9.519:

I've logged the issue with our systems again so we can investigate how we can improve it further.

Greg K

[kstrauss]

GregK, I appreciate your comments. My testing was done with 10.509 and my results seem much worse than you showed with 9.519 and are similar to your pre-9.519 image. Is it possible that somehow the 9.519 update was not carried into 10.509?

[gregk]

GregK, I appreciate your comments. My testing was done with 10.509 and my results seem much worse than you showed with 9.519 and are similar to your pre-9.519 image. Is it possible that somehow the 9.519 update was not carried into 10.509?

That fix was carried into the latest version as well. However it seems that the size of the model makes a lot of difference. When making those screenshots, I've imported the model into material 4" in diameter and resized the model to fit the material. Then I re-read your posts and imported it into the crv file that you've attached, selected MM as model units and I got worse results.

As a workaround you can make your material size way larger than you really intend. Then when importing model, make a note of its diameter, make the model fit material and import. Then go to job setup and change diameter to that of the model and select 'Scale design with job size' checkbox.

Greg K

[kstrauss]

Thanks, I'll give it a try. Perhaps as an enhancement the smoothing tolerance could be varied as a function of model size. As you noticed my STL is not large (less than an inch in diameter). My projects are mostly in metal or plastic and range between small and tiny.

[wannabecnc]

Hi Guys, I hope 2024 is bringing you all much better times than last year.
Okay, I will attach three pics of when I was importing an STL file into VCarve Pro 11.554. Please can anyone tell me, why I was able to import the STL, centre, then position and import it, BUT, then it would show on the page where it was meant to be?
I tried getting the STL from the modeling tab, and from the regular file and import route, both avenues worked until it came to showing the imported STL to where I intended it to go. I have attached the three pics showing the progress. I would certainly appreciate your knowledge and assistance in this anomaly
Kind Regards.