View Full Version : Node Noob Observations

05-16-2009, 04:09 PM
Revealing my total ignorance here ... I really only started getting into nodes yesterday, and still spent most of the day rendering, so progress is slow.

I'm starting simple, trying to do object displacement, and I'm seeing odd stuff just attaching a 3D texture directly to the Displacement node. It looks like the texture is sheared, as all the displacements are skewed toward the upper right (meaning skewed toward all 3 axes), and if viewed from a 45-degree angle (looking X-, Z+ or X+,Z-), this strange "sheared" effect it is very pronounced.

No amount of texture rotation seems to fix this, and there are no controls for "unshearing" a 3D texture. Why are the textures sheared? Is this a bug?

So I added a Spot Info node, and through a math:scale node, connected the Spot's "normal" output to Scale's vector input, which straightened out the 3D texture to look like it should from past experience with object displacement (in other words, the 3D texture is no longer sheared-weird, and the elevations are in the proper Y direction). This is just strange. I think I understand the normal spot info concept, but I DON'T get why the 3D textures look so wonky to begin with.

Now I'm seeing that the 3D texture's X and Z SCALE affect the object's deformation as expected, but the Y scale does NOT. No amount of sizing the Y scale does ANYTHING at all. I think this is weird also.

Why does the Y scale stop affecting the displacement at 1m? Is this a bug? Or a feature? :-)

The Y scale attribute is now apparently applied to the OPACITY setting, which at least is a workaround, but it just doesn't make all that much sense to me.

Am I going crazy, or is this how LW nodes are supposed to work?


05-16-2009, 05:58 PM
OK, I thought I'd better add some pictures to help communicate what I'm trying to ask here ...

Pic 1 (DispMap) shows one of the old ways of displacing an object, using good ol' Displacement Map.

Pic 2 (DispNode) shows the off-kilter result when done with the Node Editor. Note the wonkiness of the texture. It's clearly sheared on all three axes.

Pic 3 (DispNodeNormal) shows what I had to do in the Node Editor to correct this. (There may be other ways, but since I'm a total noob, I don't know of others.)

Why is this necessary? And why do 3D textures come into the Node Editor all skewed, requiring more nodes to correct the 3D textures to the way they should be? Also please notice that the texture SCALE is wrong in the node application of the displacement (compare Pic 1 with Pic 3). Do I need to add more nodes somehow to correct this problem too? If so, please tell me how to do that so the textures are scaled properly.

Thanks for any thoughtful answers. :-)


05-16-2009, 09:05 PM
I got this figured out thanks to 3d4me in the SpinQuad forum. It's the Make Vector node for displacements, same as determining which axis to displace. Makes perfect sense now. :-)