Z height.

[DarkAlchemist]

I have tried to wrap my head around this for a while now but haven't been able to so I am asking here in hopes someone can help. I may explain this badly but if so ask as I really do need this info.

G28, then G92 Z xx.xx If I want my nozzle to be slightly higher when it goes to print than what the G28 says which way do I put it? G92 Z -0.05 or G92 Z 0.05?? One will make the nozzle go lower when the first line of printing hits and the other will make the nozzle not go as low. Basically with the G92 you are trying to fake out the math to think the nozzle is not where it really is in the Z direction so when it lowers to start the first layer it will either go lower (squishing it more) or higher (raised up) from the build plate.

Anyone know which way should it be? A whole lot of stuff in Marlin is backwards and I remember when I used a Z probe that was backwards too.

[LambdaFF]

Don't do that. There is a perfectly good tool already existing Plus, you don't need to do it all the time : use M212 Z***
If negative, goes lower.
If positive, goes upper.

Use M501 to check the value beforehand.
Use M500 to save it.

[DarkAlchemist]

I have the rom turned off but it doesn't matter as my Marlin lacks M212

* M209 - S<1=true/0=false> enable automatic retract detect if the slicer did not support G10/11: every normal extrude-only move will be classified as retract depending on the direction.
* M218 - Set hotend offset (in mm): T<extruder_number> X<offset_on_X> Y<offset_on_Y>

Skips right over it and this version of Marlin is from Dec, 2015.

edit: Seems only the Printrbot's version of Marlin (its fork) has M212 from what I have gathered after your post.