Difference between slic3r and cura  

Re: Difference between slic3r and cura

Cyrille

Try KISSlicer. It's my slicer of choice and generally gives my much better prints that Cura does. I only use Cura when KISS has a problem with the model, and that's usually the model's fault...

Peter

Re: Difference between slic3r and cura

Thank you PJR, I've just downloaded Kisslicer. I don't see official setup for the MK2, would you have a setup to advise me ?
I wonder if there is a way to have a control on the way the slicer do the bridges. I would like to have the bridges that cura does on my 4th example, can I configure it with slic3r ? Or with Kisslicer ?
Do you never use slic3r ?

Re: Difference between slic3r and cura

Cyrille

I have attached my current settings - make sure that you select the correct printer though...

These settings are constantly changing, so it it up to you to ensure that they do what you want.

No, I have never used Slic3r. When I bought my first Chinese clone, I used Cura, but really was not happy. Then I found KISS and have used it ever since and never found the need to learn another slicer.

Peter

Re: Difference between slic3r and cura

Thank you for your settings PJR. I've tried to slice my prototype.
- I choosed the correct printer (prusa i3 MK2),
- the style : (20) Medium (this one seems to be the closest setting compared to slic3r by default, except for the speed but I let it like that)
- the Matl: PLA at 205 bed 45
All other settings are left by default.
The problem is when I begin to print, the temp of the nozzle is trying to reach 170°c instead of the 205 ?
I immediately stopped the print. It's a pity, I can't test it. The slicing seemed very good and exactly the way I wanted it...

Re: Difference between slic3r and cura

In general, Cura uses simple strategies, while Slic3r tries to be very clever. Sometimes the simplicity wins, sometimes the tricks the Slic3r does help.

Cura prints all lines with the constant line width. Slic3r with the default settings uses wider lines for infills. Slic3r tries to fill in gaps in the infills with short lines of variable width. Cura does not do that, but Cura produces thiner gaps as it prints infill with thiner infill lines (by default).

Slic3r tries to calculate bridge directions for each letter in separate and it does not work well in this case. I am actively looking into this issue.

Those are some of the differences regarding the examples shown.

Vojtech

Re: Difference between slic3r and cura

The problem is when I begin to print, the temp of the nozzle is trying to reach 170°c instead of the 205 ?

Cyrille

That is correct. The bed is heated as is the extruder to 170 during the initial homing. The 9-point calibration is then run and the extruder is then heated to full extrusion temperature as specified in the material tab.

This is to prevent the ooze blobs on the bed during the 9-point calibration.

Have a look at the start GCode...

Peter

Re: Difference between slic3r and cura

In general, Cura uses simple strategies, while Slic3r tries to be very clever. Sometimes the simplicity wins, sometimes the tricks the Slic3r does help.

Cura prints all lines with the constant line width. Slic3r with the default settings uses wider lines for infills. Slic3r tries to fill in gaps in the infills with short lines of variable width. Cura does not do that, but Cura produces thiner gaps as it prints infill with thiner infill lines (by default).

Slic3r tries to calculate bridge directions for each letter in separate and it does not work well in this case. I am actively looking into this issue.

Those are some of the differences regarding the examples shown.

Vojtech

That's very interesting what you are explaining, I was trying to understand why cura has got better results in this example and you gave me the answer. That's exactly what I noticed, slic3r calculates bridges for each letters in separate, while cura consider all the word in one entity. I know you are working on the improvement of slic3r and that would be great to have the choice the way slic3r calculate bridges. We could improve our prints in each circumstance. Thank you for your reply and your explanations Vojtech, this is really appreciated.

Re: Difference between slic3r and cura

The problem is when I begin to print, the temp of the nozzle is trying to reach 170°c instead of the 205 ?

Cyrille

That is correct. The bed is heated as is the extruder to 170 during the initial homing. The 9-point calibration is then run and the extruder is then heated to full extrusion temperature as specified in the material tab.

This is to prevent the ooze blobs on the bed during the 9-point calibration.

Have a look at the start GCode...

Peter

Ok thank you Peter, I'm not an expert in the reading of the Gcode, that's a very good thing. I'm always trying to clear the ooze blob just before the 9 point calibration to keep the bed clean when I do my prints. I will let it go on and post the result to compare it with cura and slic3r prints.

Re: Difference between slic3r and cura

Peter,

Have you ever noticed that the _printer.ini file uses ASCII for everything except the gcode segments. It uses hexadecimal there. Interesting.

Re: Difference between slic3r and cura

Richard

That would be because carriage returns would completely screw the ini file.

INI files can only have 1 "line" for each item. If that line contains a carriage return, everything after that is effectively lost.

Peter

Re: Difference between slic3r and cura

Cyrille (and anyone else considering trying out my profiles)

GCode is not difficult to understand and I have ensured that each line is commented.

Note that on the Printer GCode/Prefix tab, that there are 3 lines which are specific to my printer and filament and will require changing for yours.

M301 - sets the PID for my V6 with a sock
M304 - sets the PID for my bed in my office
M92 - sets the extruder steps/mm for my filament pulley with the filament I am currently using.

All 3 values will be used until the printer is reset/restarted, whereupon the default firmware values will be restored.

It is up to you whether you find the relevant values for your printer etc.

Peter

Re: Difference between slic3r and cura

Hi PJR, I succeeded in printing my first object with KISslicer (using your profiles). As promised, here's a picture and the print from slic3r to compare.

The picture speaks by itself.
- The Inside of the letters is exactly the way I wanted. It's perfect. There's a problem with the numbers which are not well defined compared to the slic3r one (perhaps an overextrusion ?). Regarding to your last message, I think I should change the M92 command if it's overextruded, or use the same temperatures used with slic3r (215°c for the nozzle and 55°c for the bed. the temperatures used with kisslicer were 205°c and 60°c).
- The estimated time was also very precise: estimated 32min, printed 31min (I used the slowest mode).
- No warping problems like I had with cura.

So thank you PJR, I'm very pleased with this first print using KISslicer, you convinced me. I think the problem I'm speaking above is just one or two parameters to adjust.
I will first try to change the temperatures (nozzle and bed, can you confirm it's M301 and M304 ?), then M92 (I'm still using prusa PLA).

Re: Difference between slic3r and cura

Cyrille

I think you will need to remove the M92, M301 and M304 lines (and reset the printer).

It has taken me a long time to get the KISS parameters refined, but they will be different for each printer/filament combination. If you do want to continue with KISS, then it will require you to try out different settings, with a few failed prints. It is quite complex when you start out, but I found that is soon starts to make sense.

I am very pleased to have been able to assist.

Peter

Re: Difference between slic3r and cura

All 3 values will be used until the printer is reset/restarted, whereupon the default firmware values will be restored.

It is up to you whether you find the relevant values for your printer etc.

Peter

Do you mean even if I choose to print a Gcode made with slic3r, it will still use the values from KISSlicer ? Even if I power off the printer ?

Re: Difference between slic3r and cura

If only a reset can restore the default firmware, will I have to readjust the "Z live adjust" and the values for left right front and back of the fine tuning of the bed ?

Re: Difference between slic3r and cura

No, not a factory reset, just press the reset button by itself, or power cycle the printer...

Peter

Re: Difference between slic3r and cura

Ok, I've pressed the reset button on the front panel and it seems I can print with my default settings with slic3r.
I want to go on with KISSlicer, you advised me to remove the M92, M301 and M304 lines (and reset the printer). You mean pressing the reset button on the front panel ?
If I remove those lines, will the printer use the default settings for temperatures (nozzle and bed) and extruder steps ? Or do I need to add new lines manually in KISSlicer ?
Thanks for your help.

Re: Difference between slic3r and cura

Hi Cyrille

It is probably best that I explain fully...

All the relevant printer settings are stored within the firmware - in the file "Configuration_prusa.h" The settings we are discussing here are the following lines:

// Steps per unit {X,Y,Z,E}
#define DEFAULT_AXIS_STEPS_PER_UNIT {100,100,3200/8,[b]161.3[/b]}

#define DEFAULT_bedKp 126.13
#define DEFAULT_bedKi 4.30
#define DEFAULT_bedKd 924.76

Each printer will require slightly different values, but the standard values above will work OK for all printers and most people are happy to leave them alone.

The 3 sets of values can be temporarily changed by using the M92, M301 and M304 codes.

If a more permanent change is required, then the amended values can be written to EEPROM (almost permanent memory) which will cause the changes to persist through a printer reset or power cycle, but maybe not a "factory reset" or firmware upgrade.

But there is nothing here which cannot be undone, even if it by issuing the M92, M301 and M304 commands with the standard values.

M92 is the code which amends the steps per unit (in this case mm) which the printer uses to move the motors. In my case, I calibrated the filament I am currently using and found I needed a different value.

The M301 and M304 commands change the PID values for the heaters. Note that this does not change the temperatures, only the calculations used to keep the temperatures at the required level.

I have upgraded the extruder heater block and added a sock, which will modify the heater characteristics which will require different PID values to maintain the temperature. While I was doing that, I did the same with the bed, as my bed is being used in a completely different environment to the printers at PR where the standard values are determined.

Hope the above helps.

Peter

Re: Difference between slic3r and cura

Ok PJR, thank you for all those explanations. I didn't think we could write on those different kind of memories only with Gcode. I think I'll need time to understand everything you're explaining, I own my MK2 only since 3 weeks...
I'm not ready yet to modify those PID values...I'm not enough experienced and for me it's quite complex. I want to thank you for taking your time to answer all my questions which may seem stupid for experienced users.
For the moment, I will just remove the M92, M301 and M304 lines (and reset the printer) like you suggested before. Then I will just modify some parameters in KISSlicer tabs (the ones I understand) to improve my printings in the waiting of improving my knowledge (and my english too, I'm french, english is a foreign language, that's another difficulty...)