Ok, So I am posting this from work, and I want to add that I will be posting a video later so you can actually see my problem.

So first of all, I am not even sure where to post this thread, so if it needs to be moved please do so, but I figured its all over the place, so General was the place to start.

So I am a newb at this, but I think I am far enough a long that I shouldnt be running into this, and I am hoping its obvious to someone.
I cant tell if the problem is in BobCad or in mach 3, or maybe in the post processor.

the Short version is:

I draw a box in bob cad,  I make a recess in the block and run a simulation and everything looks perfect on Screen. I "post and Save" the Gcode in bobCad, open it in MAch 3, and everything loads fine. but when I switch to the Tool View,  I see the box I made, but the recess toolpath is about 10-20mm beside the stock.




The long version:  (I was following this as a guide http://www.youtube.com/watch?v=O8Es52fJ1js)

- Open a new project in BobCad.

- draw a 100mm x 100mm  block  (centered)
- Draw a 50mm x 50mm Block.
- translated the part to  x,y zero.
   highlighted all of the pieces,  and then clicked on the piece to zero it.

- next I picked stock geometry and shift selected the outside box.
- next I selected the tool path and selected pocketing
- I select the geometry
- Click Finish

- I click compute toolpath.
- I click Verify

once I am here everything seems to work visually.

so I click Post and save and store the file on the HD.

So now when I head over to mach3,  I open it and move over to the tab and look at the work. I see a purple box, and a toolpath thats over to the right of the stock where its going to build the pocket.

and thats where I am confused. I dont understand where it all got confused.  I have tried it 2 different ways , once with the centering, and once with just leaving it as is.

and in both cases it appears this way.

I should mention that everything is set up for Metric, so there is a chance that something is getting screwed up, but OH GOD, I dont want to re-confirgure everything for  SAE


I hope to post the video tonight, of me running through the process, but I figured maybe someone might know the problem without seeing the video.

Sounds like you may just be needing to set the X Y Z zero in Mach to suit the code and the position you have the stock.
I will wait to see your video before I can say for sure however
Hood

here is the actual Gcode its making.



(BEGIN PREDATOR NC HEADER)
(MACH_FILE=3AXVMILL_MM.MCH)
(MTOOL T1 S1 D12.7 H127. DIAM_OFFSET 1 = 6.35)
(MTOOL T2 S1 D12.7 H127. DIAM_OFFSET 2 = 6.35)
(SBOX X-.877 Y-.877 Z-25.4 L99.123 W99.123 H0.)
(END PREDATOR NC HEADER)

%
O100
(PROGRAM NUMBER)
(PROGRAM NAME - BOBCAD1.NC)
(POST -  MACH 3 MILL NO ATC METRIC)
(DATE - WED. 11/06/2013)
(TIME - 10:25PM)

N01 G21 G40 G49 G54 G80 G90 G91.1
N02 G53 Z0.


N03 T1
N04 S1252 M03
N05 G00 G90 G54 X66.503 Y31.743
N06 G43 H1 Z2.54 M08
N07 G01 Z-12.7 F254.5827
N08 Y66.503 F496.4363
N09 X60.153
N10 Y31.743
N11 X53.803
N12 Y66.503
N13 X47.453
N14 Y31.743
N15 X41.103
N16 Y66.503
N17 X34.753
N18 Y31.743
N19 X31.745
N20 Y66.503
N21 G00 Z2.54
N22 M09
N23 M05
N24 G53 Z0.
N25 G53 X0. Y0.
N26 M01


N27 T2
N28 S1879 M03
N29 G90 G54 X30.473 Y67.773
N30 G43 H2 Z2.54 M08
N31 G01 Z-12.7 F381.8741
N32 Y30.473
N33 X67.773
N34 Y67.773
N35 X30.473
N36 G00 Z2.54
N37 M05
N38 G53 Z0.
N39 G53 Y0.
N40 M02

(END OF PROGRAM)

N41 M30
%

here is the video of me reproducing my problem.


I hope someone can make heads or tails from this.

http://www.youtube.com/watch?v=K-gSa9wvKOE

Everything is fine, all that is wrong is you have not told Mach where the offset zero position is, ie the corner of your material as you selected in BobCAD.
The cube you are seeing in Mach is your work envelope as defined by the limits set in Homing and Limits page. You may not have actually set anything up there, it will depend on whether you have limit switches and are using Soft limits.
Anyway all you need to do is jog your cutter so that it is over the lower left corner of your work piece, then click zero at the side of X and Y DROs then press Regen and it should look fine after that.
Also if you click the Display button once in Mach then press Regen you will not see the cube as you will have put Mach into work piece mode rather than table mode.
Hood

Thanks,  I hope to try that tonight!

ok, I got home and did as you said, and well it worked!  KIND OF

I swear I have ghosts in my machine.

So, here is what I did.

I powered everything up, loaded into Mach3, and they hit the Reference Home button.

and like every other time, it zeroes out the machine.  as shown the graphic bellow (look at the X).


*********************
*                                  *
*                                  *
X********************


Then , I load in the Gcode file I will attach in the next message.

- I move the bit too the block in the Bottom left of the stock.

- I zero the X, Y and Z

- Regen ToolPath.

- and click Start

This is when things go weird.

- It starts to Zero back to the top of the Mill,  but at a incredibly slow pace. like 1 mm every 5 seconds. I would love to know how to make it do this step Faster.

- Next,  it travels all the way to the Right.

*********************
*                                  *
*                                  *
********************X

- And then starts running through the cutting pattern that I did up in BobCad.  only now, its cutting from right to left. and in the video, you can clearly see it cuts from left to right.

So, I decided, something is wrong, and I will correct this.   I hit the Reference Home button. and then it starts Zeroing itself to the Right, (instead of the left)

So, NOW, I am confused, and reboot the PC, I exit Mach3 saving Nothing, reboot. and try just doing the Reference zero again.

and again, its starts Zeroing to the Right. (as seen bellow)

*********************
*                                  *
*                                  *
********************X


So I am really confused. Am I loosing it?

I took a screenshot of mach3 running through the program. , as  you can see, its processing from the right to the left.

but WHY?  I didnt change anything in the config,  did the Gcode change it? seems odd that it would.

here is the new Gcode,  its more or less the same, the stock is 200 x 50 instead of 100x100

------------------------------------------------------------------------------------------------------------------------

(BEGIN PREDATOR NC HEADER)
(MACH_FILE=3AXVMILL_MM.MCH)
(MTOOL T1 S1 D10. H127. DIAM_OFFSET 1 = 5.)
(SBOX X0. Y0. Z-25.4 L100. W50. H0.)
(END PREDATOR NC HEADER)

%
O100
(PROGRAM NUMBER)
(PROGRAM NAME - BOBCAD1.NC)
(POST -  MACH 3 MILL NO ATC METRIC)
(DATE - FRI. 11/08/2013)
(TIME - 12:17AM)

N01 G21 G40 G49 G54 G80 G90 G91.1
N02 G53 Z0.


N03 T1
N04 S1591 M03
N05 G00 G90 G54 X94.5 Y5.5
N06 G43 H1 Z2.54 M08
N07 G01 Z-2. F323.3201
N08 Y44.5 F630.4741
N09 X89.5
N10 Y5.5
N11 X84.5
N12 Y44.5
N13 X79.5
N14 Y5.5
N15 X74.5
N16 Y44.5
N17 X69.5
N18 Y5.5
N19 X64.5
N20 Y44.5
N21 X59.5
N22 Y5.5
N23 X54.5
N24 Y44.5
N25 X49.5
N26 Y5.5
N27 X44.5
N28 Y44.5
N29 X39.5
N30 Y5.5
N31 X34.5
N32 Y44.5
N33 X29.5
N34 Y5.5
N35 X24.5
N36 Y44.5
N37 X19.5
N38 Y5.5
N39 X14.5
N40 Y44.5
N41 X9.5
N42 Y5.5
N43 X5.503
N44 Y44.5
N45 G00 Z2.54
N46 M09
N47 M05
N48 G53 Z0.
N49 G53 Y0.
N50 M02

(END OF PROGRAM)

N51 M30
%

If you attach your xml I will take a look and see if I can replicate your problem.
There is nothing in G Code that could cause the  homing direction to reverse  in Mach.
Hood