Decals - What's the Secret?

daveso

Decals are some strange thing, omo. I've been trying to use them, but they're like a projection, and very difficult to place them correctly to show on the surface. Is there a way to just know its located in the correct place for visibility? I realize ithey only show during Iray render or using Iray viewport. 

SilverGirl

daveso said:

Decals are some strange thing, omo. I've been trying to use them, but they're like a projection, and very difficult to place them correctly to show on the surface. Is there a way to just know its located in the correct place for visibility? I realize ithey only show during Iray render or using Iray viewport. 

Method I used recently in putting one on a wall: make a primitive plane, and put the decal on that. Move it to desired position and then re-parent-in-place the decal to the desired object. I was having a devil of a time trying to figure out where my decal was and how I needed to move it to get it to show up, and this method at least narrowed down the possibilities.

Full disclosure: I haven't done much with decals, so there might be a better or more elegant way. 

NorthOf45

First, a decal must be parented to the object. There is a bounding box that shows in all draw modes when the decal is selected in the scene, so that will give you a good idea where the center of the decal is. The box should intersect the surface, and the Z-Axis (the blue one) must be pointing away from it. There are many adjustments to scaling and clipping, and a choice of projections and coordinate systems. Never seen a good explanation for all the features, but the defaults should be good enough to start. Most seem to load facing the positive Z-Axis (towards the user) when looking at the front, so if you want to have it on another side, you have to rotate and translate the decal. Some, specific to ground elements, face upwards.