STL: wrong IsBinary detection

[Dirk C]

Hello,

i wanted to created a report in bugtracker but i don't have permissions, so i want to report it here:

The STL file importer seems to have a wrong IsBinary detection. This file is recognized as ASCII but it's a binary:

Deathstar.stl:
https://drive.google.com/open?id=0Bx84-peUdIgZQl9UOTE1SlFlRjg

Meshlab and Repetier Host loading is fine.

See also:
https://stackoverflow.com/questions/26171521/verifying-that-an-stl-file-is-ascii-or-binary

As far as i remember this file was expoted as STL with meshlab.

Hope this helps,
Best regards
Dirk

[Jerome.D (BeanzMaster)]

Hi Dirk Thanks, we know this bug but i never (search) localised before. I'll take a look

cheers

[Dirk C]

Hi Jerome,
thanks for looking at this! Can you send me the SVN / bugtracker access so i can conribute?
Best regards
Dirk

[Andrea Menapace]

Hello friends,
I also wonder about this problem.
I have two .stl files for the same model, one processed in Binary format and the other processed in ASCII format.
Unfortunately, Binary model does not appear...
Will I overcome this problem?
Thank you

[Dirk C]

Hi Andrea,

do you have debugged the STL file IsBinary detection? Can you post the STL file?
Place a breakpoint in
~~~
procedure TGLSTLVectorFile.LoadFromStream(aStream: TStream);
begin
..
isBinary := True;
i := 0;
while i < 80 do
begin
if (headerBuf[i] < #32) and (headerBuf[i] <> #0) then
begin
isBinary := False;
Break;
end;
Inc(i);
end;

..
~~~

My bugreport was about the wrong IsBinary detection..
Best regards
Dirk

[Andrea Menapace]

Hi Dirk,
to begin thank you for availability.

I work with scanners for my dental laboratory that generate .stl ASCII files.
I did a small project with GLScene to open these files.
Now files are sent to me .stl Binary files generated by Intraoral Scanner
Unfortunately I can not open them with my project but it would be indispensable to me.

I attach an example of files I can not open.

Thank you again for your kindness.

Andrew

P.S. Sorry for my English... ;)

[Jerome.D (BeanzMaster)]

Hi Andrea, Hi Dirk I take a look, it's just a small error change :In GLFileSTL around line 145

isBinary := True;
i := 0;
while i < 80 do
begin
if (headerBuf[i] < #32) and (headerBuf[i] <> #0) then
begin
isBinary := False;
Break;
end;
Inc(i);
end;

by

isBinary := False;
i := 0;
while i < 80 do
begin
if (headerBuf[i] < #32) and (headerBuf[i] <> #0) then
begin
isBinary := True;
Break;
end;
Inc(i);
end;

That's it

I'll update SVN later

Bye

[Dirk C]

Hi Jerome,

isBinary := True;

did the trick! Generally STL import works very good and now even better..
Thanks & best regards
Dirk

[Dirk C]

Sorry, but this fix does not work, see attached binary STL.
This file was loading fine before the fix, so it's a regression..

[Dirk C]

Hi Jerome,

i've fixed the STL format detection, sanity checks done as suggested.
I've tested against a few STL and seems to work fine now.

Attached is the SVN patch. You can can send me SVN account to dirk(dot)carstensen(at)gmail.com, i have more fixes and enhancements done..

Best regards
Dirk

[Pavel Vassiliev]

Hi Dirc,
I've updated GLFileSTL using your patch, so if you have any other bug fixes send your patches to check and repair units

[Andrea Menapace]

Hi Dirk, hi Jerome, thank you.
I saw your great work to update GLFileSTL.
I tried to change the variation on [isBinary:=True or False] suggested by Jerome and it works by alternating the opening of files.
Then I updated with Dirk's suggested text to intercept the file type, but I still report the error "The STL file is not long enough (% d bytes)."

Any other precious suggestion?
Thank you very much.

[Andrea Menapace]

Hi Dirk

Good job!
Now everything works best!

Thank you.

[Bottleneck]

Hello Jerome,

I am working with Lazarus and GlScene to create G-Code for LinuxCNC from 3D files.

I encountered a problem loading an ASCII STL file. Within the first 80 Characters there is a LF (#10) in this file. So this routine detects the file as being binary.
I changed your if clause. First I removed
and (headerBuf[i]<>#0)
and added:
and (headerBuf[i]<>#10) and (headerBuf[i]<>#13)
and it worked perfect.

Afterwards I found that there is a #0 in the header of every binary STL file. I did not find any #0 in all of my ASCII STl files. So I think to detect an binary you only have to detect #0 within the first 80 characters.

This is the code I am using now:
It works fine for all of my STL flies.

  isBinary:=False;
   i:=0;
   while i<80 do begin
           if (headerBuf[i] = #0) then begin
                 isBinary:=True;
                 break;

Could you please check the branch "GLScene_LCL". I did not find the change above.

Thank you very much

[Jerome.D (BeanzMaster)]

Hi Bottleneck, sorry for answer just now, i was very busy
Thanks i'll do the change. Great !!!

Can you send or tell me where i can found STL file for testing ?

the code is in : source/fileformats/GLFileSTL.pas

Thank you

EDIT : the current code is :

 isBinary:=True;
   i:=0;
   while i<80 do begin
     if (headerBuf[i]<#32) and (headerBuf[i]<>#0) then begin
         isBinary:=False;
         Break;
     end;
     Inc(i);
   end;

Can you test with it ? Thanks in advance