Hello,
I try to make a mirror on a line.
I have put the pivot point in the 0 of the X axis. The pivot point are also align with the world orgin.
When I apply the Mirror Modifier, my new line are not in the same axis that the source line.
I need Help, I have try reset transform, etc…
Thanks.

3ds Max 2013
Dual Xeon 5670 - Nvidia Quadro FX 4800

I try to put the scene in attachment (doesnt work in the 1st post...)

3ds Max 2013
Dual Xeon 5670 - Nvidia Quadro FX 4800

ok. here the scene…

3ds Max 2013
Dual Xeon 5670 - Nvidia Quadro FX 4800

	Attachment
curvemirrorproblem.zip

Something clearly not right there - try this:-

Create a new Line, along the world Y axis (use grid snaps to be certain). Just a single segment (2 vertices) will be sufficient.
Align the new line to your existing one - pivot to pivot, position (XY&Z) only (uncheck all the lower (rotation/scale) options).
With the new line still selected, Attach your old line to it.
Select the Spline which was the new line and delete it.
Apply the Mirror Modifier, Turn on the Copy option (assuming that’s what you need).

You need to watch your System Units and the distance you are from the origin. Your SUs are Meters, your object is 84876.001mm long, which is 84.876001M. Max does NOT like working with many decimal places, but that’s what you’re asking it to do. It can cause viewport errors and worse, so bear that in mind.

Max 4.2 through 2013.
XP-64 (SP2)
NVidia 9800GTX-512 (Driver 266.58).
Core 2 Quad Q6600 2.4GHz, 8Gb Ram, DX9.0c.

Nice solution, thanks.
Another bug in max!

3ds Max 2013
Dual Xeon 5670 - Nvidia Quadro FX 4800

Yes, but that’s strange, when I reset the pivot it still not aligned with the world axis…

3ds Max 2013
Dual Xeon 5670 - Nvidia Quadro FX 4800