How can I skip the first x layers of a print?

Hello,

I have already posted this in the Vellemann K8200 forum but didn´t get a reply yet, so I hope someone here can help me out.

A co-worker printed the top part of [www.thingiverse.com] and didn´t notice that slic3r 1.1.7 produced an error message and didn´t slice the last top layers. Now, I have checked that slic3r 1.2.6 has that problem fixed and was able to slice without problems.

I now want to skip the first 101 layers (starting height would also be known) and start printing with the remaining layers. I have examined the g-code but there are no direct z-axis movements and I wasn´t able to figure out which code is responsible for that. Here is part of the g-code that I think might be the layer change:

G1 X95.814 Y109.594 E5.92641
G1 X95.599 Y109.264 E5.92843
G1 X95.386 Y108.732 F12000
G1 E0.92843 F3900
G92 E0
G1 X95.014 Y107.31 F12000
G1 E5.1 F3900
G1 X95.532 Y106.854 E5.10353 F900
G1 X95.87 Y106.731 E5.10537
G1 X96.266 Y106.513 E5.10768
G1 X96.349 Y106.394 E5.10842

How can I see where the commands for layer 1 start and where layer 101 ends so I can deleted the g-code for the first layers?


Lars

Keep looking. Layer changes will have an explicit Z move. That's a retraction and repositioning move within a layer, not a layer change.

Hmm, seems like I was blind. Don´t know what I was searching for before, but now I think I found it.

These are the codes, right? G1 Z...

G1 X86.852 Y122.502 E5.27336
G1 E0.27336 F3900
G92 E0
G1 Z17.4 F12000
G1 X83.236 Y114.034 F12000
G1 E5.1 F3900
G1 X83.141 Y113.746 E5.10155 F1800

Find the height of the layer you need to start the print by multiplying the number of layers-1 by layer height and adding 1st layer height. e.g if you want to skip the first 101 layers then you will need to start printing on layer 102. If your layer height is 0.25 and first layer height is 0.4, then layer 102 will be at height (101 x 0.25) + 0.4 = 25.65mm.

So with a text editor search for the line that contains the characters "Z25.65" (there should only be one line with those values) Check the line above, if it is a retraction command (G1 Exx with no X or Y parameters), keep that line as well but delete everything before it. If you use relative extrusion then you can just print that partial file. If however you are using absolute extrusion commands, you will need to send the command "G92 Exxx" to the printer before printing, where "xxx" is the last E value in the part of the file you deleted.
Dave

@Dave: Good point regarding absolute/relative values.

Seems like it was set to relative as I started printing before I saw your post and the first layers look fine so far. Will lose tiny parts that are not connected to the rest of the to be printed brain, but that´s ok. Most brains seem to be missing some parts ;-)