Skeinforge Powwow

This is the skeinforge announcements and discussions thread. Any questions, suggestions or comments about skeinforge should be posted here or emailed to me at:
perez_enrique@yahoo.com

The skeinforge wiki manual, which you are welcome to contribute to, is at:
[www.bitsfrombytes.com]

A description of the GPL skeinforge is at:
[reprap.org]

The most recent skeinforge can be found at:
[members.axion.net]

another sometimes out of date version is at:
[reprap.svn.sourceforge.net]

The skeinforge contributions thread is at:
[dev.forums.reprap.org]

The skeinforge settings thread is at:
[dev.forums.reprap.org]

Assuming you have python, which can be downloaded from:
[www.python.org]

to run skeinforge; in a terminal in the same folder as skeinforge.py, type:
python skeinforge.py

Edited 3 time(s). Last edit at 10/22/2009 02:03PM by Enrique.

The option to have a different feedrate for the perimeter has been added to speed.py. The updated skeinforge is attached, in subversion and at:
[members.axion.net]

Comb between islands has been improved and a corner rounding bug when importing an incorrect mesh in slice was fixed. The "Save Preferences" button has been moved to the far right of the dialogs, and the cancel button has been moved just to the left, to follow the gnome interface a bit. More color has been added to the buttons and skeinforge has been sped up.

Weaving the filament is now largely done. The next change will be to import slice formats as well as triangle meshes.

Cheers,
Enrique

Edited 1 time(s). Last edit at 01/05/2009 12:33AM by Enrique.

The structure of skeinforge has been changed to import slice formats as well as triangle meshes. The updated skeinforge is attached, in subversion and at:
[members.axion.net]

Slice_shape has been divided into carve and inset. Also because the slice formats have a layer thickness but don't have an extrusion diameter, the primary parameter is now layer thickness. To change your current parameters to the new parameters, check the extrusion width, extrusion height (which is now layer thickness) and extrusion diameter in your statistics file if you have one, otherwise you can get the parameters by looking in the comments in the gcode file, if you don't have either, try running a test model with "Print Statistics" in the Statistics tool on. However you get the old parameters, set the layer thickness to the old extrusion height, then divide the extrusion diameter by the layer thickness to set the "Extrusion Diameter over Thickness" ratio in carve and divide the extrusion width by the layer thickness to set the "Extrusion Width over Thickness" ratio also in carve. Then divide the extrusion perimeter width (which can be found in the comments only) by the layer thickness to set the "Extrusion Perimeter Width over Thickness" ratio in inset.

Then in general, go through carve and inset, read the help files, and set the parameters to whatever you had in slice_shape. Also, nozzle_wipe has been renamed wipe, so if you're using nozzle_wipe, transfer those parameters to wipe.

Thanks to Micheal Duffin, there is now an import plugin for .slc files. An explanation of the SLC format can be found at:
[rapid.lpt.fi]

Thanks to David Cowden and xsainnz, there is now an import plugin for svg files of a specific svg format. There are no scripts to produce that svg format yet, but anyone who wants to can use the template file svg_template.svg in skeinforge_tools to make that svg format. If you just want a quick hack, all skeinforge actually looks at is the metadata, text and path information, an example of which is below.

Finally, the "Turn Extruder on Early" option in raft has been moved to oozebane and renamed 'First Early Startup Distance over Extrusion Width'. This preference is the ratio of the distance before the first thread starts that the extruder will be turned off over the extrusion width. This value should be high because, according to Marius, the extruder takes a second or two to extrude when starting for the first time, so the default is forty.

Cheers,
Enrique


Layer 1, z 0.1Edited 2 time(s). Last edit at 01/19/2009 01:32AM by Enrique.

Hi Enrique

Using the January 5th version if I hit Carve button I get the following in the command window.
Am I doing something wrong or have I screwed up my preferences?


C:\PyTools>python skeinforge.py
Exception in Tkinter callback
Traceback (most recent call last):
File "c:\python25\lib\lib-tk\Tkinter.py", line 1403, in __call__
return self.func(*args)
File "C:\PyTools\skeinforge_tools\skeinforge_utilities\preferences.py", line 2
38, in displayTool
pluginModule.main()
File "C:\PyTools\skeinforge_tools\carve.py", line 396, in main
preferences.displayDialog( CarvePreferences() )
File "C:\PyTools\skeinforge_tools\skeinforge_utilities\preferences.py", line 3
0, in displayDialog
readPreferences( displayPreferences )
File "C:\PyTools\skeinforge_tools\skeinforge_utilities\preferences.py", line 6
4, in readPreferences
text = gcodec.getFileText( preferences.filenamePreferences )
AttributeError: CarvePreferences instance has no attribute 'filenamePreferences'

---

Regards

Ian

I am getting similar errors, waiting for enrique to have a look, Were you using a .slc or .svg as you input file format?

Skeinforge is now working correctly, Download latest release!!
.slc import function works a treat.

Well done Enrique

Hi
I downloaded the Jan 16th version.

Hitting Carve button no longer generates an error but now the Slice generates an error:-


C:\PyTools>python skeinforge.py
Exception in Tkinter callback
Traceback (most recent call last):
File "c:\python25\lib\lib-tk\Tkinter.py", line 1403, in __call__
return self.func(*args)
File "C:\PyTools\skeinforge_tools\skeinforge_utilities\preferences.py", line 2
38, in displayTool
pluginModule.main()
File "C:\PyTools\skeinforge_tools\slice_shape.py", line 926, in main
preferences.displayDialog( SlicePreferences() )
File "C:\PyTools\skeinforge_tools\skeinforge_utilities\preferences.py", line 3
0, in displayDialog
readPreferences( displayPreferences )
File "C:\PyTools\skeinforge_tools\skeinforge_utilities\preferences.py", line 6
4, in readPreferences
text = gcodec.getFileText( preferences.fileNamePreferences )
AttributeError: SlicePreferences instance has no attribute 'fileNamePreferences'

---

Regards

Ian

Hi Ian,

The slice_shape tool has been replaced by carve and inset. So delete slice_shape and everything should go well, and while you're at it delete nozzle_wipe if it is still there. If skeinforge still doesn't work, try deleting everything and getting an entirely new copy from:
[members.axion.net]

E

Hi Enrique

Once again many thanks, I use Skeinforge on my main PC and the PC running my Repstrap.
I had to delete and reinstall on Repstrap PC to get it working cleanly.

On the main PC when I use a help button firefox comes up instantly with the help but on the Repstrap PC it takes ages, upwards of 20 seconds. Any idea why that might be?

---

Regards

Ian

On my computer, when I bring up Firefox after turning on, it takes a long time to come up. If I then close it and open it again it takes less time to come up.

I speculate that it may that when Firefox starts up, it loads some libraries and plugins. When it is shut down, Firefox is removed, but some of the libraries and plugins like Flash may be cached somehow. I don't really know.

All I know for sure is that when using skeinforge, it is best to have a browser running. With a browser running, when the help is brought up or carve is run and the svg slices are displayed, Firefox comes up quickly and without warnings. If I run carve when Firefox is not running, the carve svg file displays in Firefox, but there are warnings in the console about Flash which I dimly remember being about having the wrong user or something.

E

Hi Enrique

I am having a little trouble understanding oozebane. The preferences in the help file I have don't seem to match the preferences you can change. I am trying to increase the distance that the extruder shuts down before the end of a thread. Which preference now controls that? I also need to reduce or remove the time the extruder starts the thread. My extruder seems to start extruding instantly but oozes a lot after turn off.

---

Regards

Ian

Quote

My extruder seems to start extruding instantly but oozes a lot after turn off.

Strange, I find that the amount oozed is a deficit that needs to be made up at the start of the next thread.

---

[www.hydraraptor.blogspot.com]

Hi

Mine might be the same. I am getting a big blob where a thread starts & stops which I think comes after extruder motor switch off. I have noticed my extruder motor takes some time to stop. My plan was to switch off miles early so I get a deficit of material and then slowly shorten the time until I get a good result. My heater may be acting differently to the norm. I have had several that worked poorly with very slow heat up times so now I have a Stainless Steel tube with insulated nichrome wrapped right at the end by the nozzle. I get a very fast response to heat commands but have inconsistency when I first start to extrude, sometimes it does not even start without a helping hand pressing the ABS into the extruder ( A BfB Mark 2 ). Once it starts it seems OK.
I may make another one with the nichrome spread up the tube to see what difference that makes.

---

Regards

Ian

Yes you are seeing exactly the same problem I have had with stainless steel barrels. They work to start with as long as you keep the filament moving. When it stops the heat halfway up is enough to take it past the glass transition point but not melt it. When you push it it just expands to form a plug that needs a lot of force to shift.

I don't think spreading the heater up the tube will help, it will just cause the problem to occur higher up.

You need to make the transition zone very short, like 5mm. I think the only way to do that with SS is to have a very thin walled section with a heatsink above it. Having said that I have not been able to make it work with SS.

---

[www.hydraraptor.blogspot.com]

Ian,

Thanks for pointing out that the oozebane help file and preferences don't match.

The distance that the extruder shuts down before the end of a thread is controlled by the "Shutdown Distance Over Extrusion Width" preference. This preference should actually be called the "Early Shutdown Distance Over Extrusion Width" as it is in the help. It will be renamed in the next skeinforge release, which will be in roughly a couple of weeks. For now just increase the "Shutdown Distance Over Extrusion Width" preference.

I haven't used oozebane so I might be talking rubbish, but I would think that "Shutdown Distance" should not be "Over Extrusion Width". The thinner the filament I would expect the longer the ooze to go. I certainly can't think why it would be any shorter.

---

[www.hydraraptor.blogspot.com]

Hi Enrique

Thanks, I should have realised that myself. Spent too much time in front of the PC.
Just to confirm. If I always want the extruder to shut off early "Minimum Distance for Early Shutdown over Extrusion Width (ratio): " should be 0 and the distance is set by "Shutdown Distance over Extrusion Width (ratio):" as you stated in your message.

if I dont want the extruder to start before the thread "Early Startup Maximum Distance over Extrusion Width (ratio):" should be 0.

I am getting a blob of extra material at the start/stop of the perimeter thread which I think is the extruder delivering a fair amount of material after it is turned off. I want to ensure the extruder is not turning on early to eliminate that as the problem. It all happens quite fast and I am trying to establish exactly the cause of the blob.

---

Regards

Ian

Ian,

Yup, that's the way it is.

If you're wondering if oozebane is doing weird stuff, just test it by unchecking the "Activate Oozebane" checkbox.


Nophead,

The assumption behind the "Over Extrusion Width" is that a big nozzle would have a longer barrel and therefore would ooze for a longer distance. However right now all the barrels are the same size, as you point out it's just the nozzle or feed rate that is being changed.

If people prefer that the oozebane preferences be changed to absolute units instead of being relative to the extrusion width or people want the preferences to stay the way they are, just send me a message, either by the forum software or to my email address at:
perez_enrique@yahoo.com

I'd prefer people send me the votes instead of posting in this thread, so as to not clutter up this thread with vote posts.

For the future, can someone recommend a good way to have online votes?

My unanimous decision, the oozebane parameters have been changed from relative to absolute. The votes follow:
Nophead wanted it
Ian voted for
Wade voted for because Nophead wanted it

Ian found a couple oozebane bugs, which have been fixed.

The xml plugin has been added in import_plugins folder. It imports Art of Illusion XML, so now the Art of Illusion Constructive Solid Geometry can be imported and sliced directly.

It is no longer required to turn Art of Illusion shapes into triangle meshes in order to slice them. It is now best to keep them as in their original form, then export the scene as an xml file. As a side effect since the entire scene is carved at once, if you want to fabricate several objects at the same time, just have them all in the same scene, making sure their bottoms are all at the same height and that they have a sufficient separation between them. The instructions on how to export as xml follow below.

The updated skeinforge is attached, in subversion and at:
[members.axion.net]

Enrique



An xml file can be exported from Art of Illusion by going to the "File" menu, then going into the "Export" menu item, then picking the XML choice. This will bring up the XML file chooser window, choose a place to save the file then click "OK". Leave the "compressFile" checkbox unchecked. All the objects from the scene will be exported, this plugin will ignore the light and camera. If you want to fabricate more than one object at a time, you can have multiple objects in the Art of Illusion scene and they will all be carved, then fabricated together.

By coincidence I just blogged a simple way to put multiple objects in an STL file and print them together: [hydraraptor.blogspot.com]

---

[www.hydraraptor.blogspot.com]

Hi Enrique,

There appears to be a critical bug in the latest version of Skeinforge.
With the default configuration, the Z values don't increment between the layers.
The layerStart comments show the correct Z values, but the G-code Z values are always the same.

---

~/= Marius

--
We are Elektropeople for a better living.
[reprap.soup.io]
[www.metalab.at]

Hi Marius,

Thanks for pointing out the z increment bug. After a while I replicated the bug and found it was in tower.py.

The bug fixed skeinforge is attached, in subversion and at:
[members.axion.net]

On an unrelated note, there used to be a bug where skeinforge would occasionally omit objects, usually small holes. This was fixed a while ago.

Edited 2 time(s). Last edit at 02/23/2009 01:37AM by Enrique.

Behold, a slow pure python isometric viewer, has been added to the analyze plugins. The viewer is simple, the viewpoint can only be moved in a sphere around the center of the model by changing the viewpoint latitude and longitude. Different regions of the model can be hidden by setting the width of the thread to zero. The alternating bands act as contour bands and their brightness and width can be changed. The layers will be displayed starting at the "Layer From" index up until the "Layer To" index. All of the preferences can be set in the initial "Behold Preferences" window and some can be changed after the viewer is running in the "Behold Dynamic Preferences" window. In the viewer, dragging the mouse will change the viewpoint.

New in export, if there is a file replace.csv, export will replace the word in the first column by its replacement in the second column. There is an example file replace_example.csv to demonstrate the comma separated format, which can be edited in a text editor or a spreadsheet.

Thanks to Marius another oozebane bug was found and squashed, as well an extruder off bug in cool was fixed.

The updated skeinforge is attached, in subversion at:
[reprap.svn.sourceforge.net]

and at:
[members.axion.net]

Cheers,
Enrique

I've just done a really good print using support material I'll post pics as soon as I can it is a dome on top of three slender posts. It worked fine but removing the support material was difficult and I broke the model getting it out. Would it be possible to have the material build up in a crossing pattern more like the infill. Then i think it would be possible to remove it a strand at a time if required when it is near a delicate object.

---

Ian
[www.bitsfrombytes.com]

cool work on the support structures! I just posted a few pictures of a part with support structures: [reprap.soup.io] (sorry the flickr importer messed up the order of the pictures)

It would really be useful to set the PWM rate separately for the different kinds of layers - especially support. It was very hard to remove the material from the object.but i know that if you print with a too low extrusion rate the model breaks very easily which would be perfect for support.

hi enrique!

Today I tested the support material functinality A little more. I wanted to print a hollow sphere:

[www.flickr.com]
[www.flickr.com]
[www.flickr.com]

It worked almost perfect. It generated support structures on the bottom and on the inside of the sphere BUT it also generated support structures on top of the sphere too!

I attached the stl and my settings and also the sliced gcode as a zip file. maybe you can find out what causes this unecessary support structures on top.

Still even with this bug I was able to print an almost hollow sphere!

---

greetings
wizard23
[reprap.soup.io]

Hey, Enrique:

I'm working on a slicing script for STEP files, that will output svg based on svg_template.

I am assuming that your code expects only M and L commands in the path segments ( moveTo and LineTo).

To create this, I'll convert curves to approximated collections of line segments.

However, svg paths also supports curve moves. Cubic and bessier curves sound hard, but elliptical arcs might not be too hard, and might be worth it since many shapes would be composed of straight lines and arc segments...

What are your thoughts about how far into the toolchain it makes sense to preserve curves in their original form, vs an approximation?

Hi Dave,

It would be neat to use curves, but the skeinforge inset algorithm only understands line segments, so it would not even be possible for skeinforge to preserve curves. For curved shapes, we just have to use many segments, and as long as the approximation error is smaller than the filament width, that's good enough.

Ok, sounds good. Maybe i'll put some comments into the svg file when i know the segment was a curve. I'll also make sure it is possible to control the approximation tolerance. Of course when reading stl this will not be a problem, but for STEP and IGES it will be.

Do you know if AOL will export STEP or IGS?

I am having problems producing a U shaped object because, on the concave side, the shell shrinks away from the fill. Any suggestions for Skeinforge parameters to get round this problem would be appreciated.

Jon