Fusion 360 post processer_MPCNC measurement off

Fusion 360 old code doesnt work anymore with their update to Hobby version.
I added the Post processer written byguffy1234/mpcnc_posts_processor and I am using Marlin.
Whats happening is for example. A box in made Fusion 360 is 130mm.
Fusion 360 is also set to mm.
But when I run the script it runs at 51mm.
Repeitor Host is what I am using to run the script. Scaling is set to MM.
I have checked all the setting I can find in Fusion 360.
If I run an old script the measurement are good.
If I use Estal Cam the measurements are good.
I am running a Ramps 1.4 with Marlin that I purchased from V1 Engineering.
Everything runs as it should.
Its when I use the the MPCNC post processer that was written for Fusion 360 that I have issues.
Any help would be great.

I don’t have an answer to your specific question, but Don Gamble did a rewrite of the guffy post processor. You can find a link to it in this post.

When you say “runs at 51mm,” have you taken a look at the g-code to see what size it thinks it is cutting? I’ve not used Fusion 360 for CNC work in a few weeks, so if this is a recent change, I’ve not seen it. Historically the big change to the hobby version of Fusion 360 was the removal of rapids. The result was the Z axis being driven at too high of a feedrate and therefore losing steps.

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Is anyone using this Post Processcor with Repetier host?

Though it is not typically how I do things, I have used Repetier-Host with Don Gamble’s version of the post-processor in the past. Repetier-Host can insert a few g-code commands depending on the settings (and any start/end code you’ve added), but I cannot think of anything that would cause your cuts to be off by that specific amount. Usually g-code is g-code, and it doesn’t matter how it is delivered to the control board. If you upload the g-code file to a post, I can take a look and see if I can spot any issues.