How 3d mapping displacement works?

[fabrice_barbey]

Hi all, newbie question here,

I put a VrayDisplacementMod on a chamfered box but it doesnt work well :
- with 2D mapping I've got discontinuity seams
- with 3D mapping the displace does absolutly nothing (so I cant use the "keep continuity" option

Should I use the VrayMtl's displace slot? But it has not options.
Is there a hidden switch somewhere?

[M.Max]

- with 3D mapping the displace does absolutly nothing (so I cant use the "keep continuity" option

Uncheck "use object material " option and 3D method will works fine.