when decal direction be same with mesh's normal,some wrong will happen.

[tanyongdahaoren]

As the picture,I want to get the right effect
Anyone help me?

[tanyongdahaoren]

Sorry,My question should be :
when decal direction vector orthogonal to mesh’s normal vector

[tanyongdahaoren]

Anyone help me ??

[tanyongdahaoren]

Anyone help me ??

[Niberspace]

Just rotate the decal so that it’s facing both surfaces