Hi everyone

Having trouble with creating an emission object with a colour ramp in it. What I have is a cylinder say 1/2mtr long and 20mm Dia at one end I have an object red in colour at the other end I have an object blue in colour. The objects at this stage are not important only as reference. At the end of the cylinder where it touches the red object I want it to emit red light and at the other end emit blue light where the blue object is and then ramp to a that purplish colour in the middle of the cylinder. basically the whole cylinder to emit light but have that light colour colour change from red to blue along its length.

Have been unable to find any tutes on achieving this and everything I have tried so far has failed badly. Any help much appreciated.

Incantrix

All my attempts so far and this is the best I have gotten it to.

No blending at all from one colour to another

Incantrix

Wish I could help on this one but Emissions is not something I fully understand myself hopefully someone will chime in soon

Me either as I rarely use them prefer to light stuff with hdri's But always trying to find new and interesting ways to do things.

Incantrix

With the help from someone at BA I managed to get it pretty dam close to what I was after.

Just need to center it a bit more and should be good

Incantrix

I am glad you got some help

Another way is to use a texture instead of a colour ramp. Any image can be used as an input into the emission node. UV map your object using "project from view", size your unwrapped UV object to fill the texture space of your image/gradient and then add an emission shader with your image/gradient as the input into the emission node and your done.

Ohhhh, nice Keppel.

Just another quick example of how using a gradient as a texture can be used in the context of your question.

Wow thanks for that Keppel never actually thought of using a texture map. Which by rights should keep the colours accurate if the emission strength is ramped up which it didn't do using the colour ramp as the blue and red looked like they mixed with white. The scene I'm using them in has 12 of them all different colours at each end but doing gradient maps in ps wouldn't be an issue at all if the end result is as you showed.

(ps really need to do my test renders in a box shows the lighting in a much better way :) )

Incantrix

Another nice one Keppel.

Thanks for the info Keppel I knew someone would come up with an answer