Controlling Mapped Textures

Sometimes, you want a texture mapped to an object, but not the whole texture. For example decals applied, or perhaps just a proportion of the object has this secondary texture, etc.

If you want to do it on border lines that MATCH the geometry of the object, ie. a group of faces that will have this other texture, then it is easily done by just using the Assign command on those faces.

For those cases where you don't want it to make the change on face borders, what to do?

Empty-controlled mapping to the rescue.

With this technique, the original set-up of faces makes no difference. The empty will control how the texture is "available" for the object.

To show what I mean... look at the following simple (and rough) ;) anim to show what I mean. There is NO changing of the object itself or its assigned faces. The only "movement" in the anim is the repositioning of the empty.

http://www.jamesalexander.de/EmptyControl.gif

All you need is an Empty which will control where the image is mapped. Remember that the mapped image will always show (unless you change the relevant axes) in the POSITIVE X and Y of the empty. The Z axis will control how deep the texture is allowed to affect the object.

For this, you must set the Coordinates in the image mapping to Object, and then choose the Empty. Additionally, set "Clip Cube" rather than Repeated so that the texture stops at the boundaries of the Empty.

There are MANY applications for this, even though the example is quite simple and might seem not so useful.

As an example, if you had a plastic goblet and you wanted it to slowly (ie. smoothly) turn from plastic to gold, then this would be the way to do that. The movement of the Empty would make it all happen smoothly.

Another (non-animated) example... say you have made a glass and later you decide that you want to make a metallic, gold rim at the top of the glass. It does not matter the geometry of the object (ie. where the edges of the faces are), the empty can control as much or as little as you want without having to have any concern with the underlying geometry. Cool!

Peace

James

Oh this will be helpful for something I am working on! I'll have to spend some time experimenting with this :D

Cool, glad you find it useful. :)

Here's another example... nothing changed in this one but the empty.

http://www.jamesalexander.de/EmptyCntrldTextr_.png

The cubes are all one object (even the dull ones) and the Empty controls a Conical Gradient that was made in Xara. The main texture is the bright Emitting one. The three dull ones are the same, except with Emit Off. You can see that their color changes too, as controlled by the Empty...

In this one, again the Empty moves, which is controlling the (same) texture, which alters the coloring of the cubes.

http://www.jamesalexander.de/EmptyCntrldTextr2_.png

Have fun and you're bound to find many uses for this one (mercury moving up in a thermometer, a barber pole!, etc.). You could use the Alpha transparency tip along with this one and use the Empty to constrain where the cut is.

James

Looks like you are having fun teaching James. Good work. I also have been following these threads with interest.

Yes, it is fun sharing what I've discovered in the hopes someone else can use it. Or, yes, I like teaching. ;)

Hey...I haven't noticed a Scribble yet... when you post one, I'll try it at least once! :)

Take care, Larry...and I'm glad you're enjoying these threads.

Peace

James

Intermission...

How many blocks do we see? ;)

Attachment 84411

Peace

James

From the title of your picture, I'd say: only one, and 2 mirrors reflecting... Very nice !

Good work, Guy. Yeah, guess maybe I should have changed the name of the file. ;) [I forgot about it even being directly visible....DOH!]

Glad you liked it... you can tell it was an experiment, but I think Blender did pretty well. In the original, the camera was off-center and I then generated the frames as it moved to the center. It was a cool effect, but the one with camera in center looked most interesting...

Peace

James