How to do a candle in iray

Sertorial

Hi

I have a nice candle prop and I have parented a small oval primitive to the wick (to be the flame) and then I've selected the oval material and set it to emission.

It gives off light ok, but I want it to be a bit more realistic looking. Like for one thing maybe a more flame shape, and more of a glow.

Has anyone any pointers as to how to make a nice candle flame?

Thanks

TabascoJack

If it's a 2-d primitive, I'd consider finding a good candle flame photoshop brush, and use it to create a texture for the Emissive slot.  Then desaturate it to black and white (you may need to increase contrast) and create an opacity map.  When rotated correctly, it should give you a good flame shape.  Set the Emissive property to emit on both sides of the plane.  You also might (ok, will) want to cheat and add a point light as well.

 

frank0314

You need to use a transmap to get it to look like a flame. You can also try modeling a flame shaped like a tear drop.

Tobor

Not to be the curmudgeon, but this is very easily done in Photoshop. I personally never bother with this stuff in the render. Photoshop brush effects look better, and are more controllable.

I would certainly add that point light where the candle is, make its emitter a bit larger, and set its Render Emitter property to off. Adjust the luminance and color to achieve the local lighting effect you want. The flame itself is then added in Photoshop using a brush and maybe a layer mask.

Sertorial

Thanks for all these ideas, but I am not sure how to do transparency maps. Surely someone must have produced a candle flame or shader for iRay already?

I am reasonably happy with my oval primitive (it's usually only seen from a distance anyway), but I can't get it to give that glow effect (i.e. a diffuse blob around the flame). Is that best done in postwork too?

TabascoJack

Tobor said:

Not to be the curmudgeon, but this is very easily done in Photoshop. I personally never bother with this stuff in the render. Photoshop brush effects look better, and are more controllable.

I would certainly add that point light where the candle is, make its emitter a bit larger, and set its Render Emitter property to off. Adjust the luminance and color to achieve the local lighting effect you want. The flame itself is then added in Photoshop using a brush and maybe a layer mask.

To be honest, this is usually what I do also.

Tobor

Sertorial said:

but I can't get it to give that glow effect (i.e. a diffuse blob around the flame). Is that best done in postwork too?

Iray has a bloom filter (http://docs.daz3d.com/doku.php/public/software/dazstudio/4/new_features/4_8/start), but it effects the entire scene. You can either try to balance the bloom with the other highlights in the scene, or do two renders, one with and one without the bloom. You could then comp them in Photoshop, or whatever other graphics program you use.

Still, if it's just a glow, then yes, post work alone is usually much faster.

Sertorial

ok, so I have added a point light and it gives the right sort of effect (candle test 1)

I have found some fire brushes and installed them. But how do I get the different flame colours? )you can only set the brush to one colour at a time) And how do I get it lookingh bright (like an actual candle? See my attempt at adding the flame in photoshop (candle test 1 + postwork). It looks awful

mjc1016

Sertorial said:

ok, so I have found some fire brushes and installed them. But how do I get the different flame colours? you can only set the brush to one colour at a time

What I've done in the past is to create a new image, about 200 x 200 with a transparent background and size the brush to just fit in it.  Then make several layers each with a different color that makes up the flame.  Then play around with them to get a pleasing mix and then merge them into a single layer.  Then save the flame.   The when I want it in the scene, just open that flane and size appropriately....

Sertorial

actually, my original methid seems to work better. The first image has no point light at all but instead a little oval primitive set to be an emitter. Then in the second image, I duplicated the layer, deleted everything but the "flame" and just applied a Gaussian blur. I know it's not all that like a flame shape but it's ok. And I really don't know how else to do it.

Thhoughts?

Tobor

Sertorial said:

I have found some fire brushes and installed them. But how do I get the different flame colours? )you can only set the brush to one colour at a time) 

There are numerous ways, but one way is to create a new layer above, then add a layer mask to it. Put the brush in the *layer mask* (not in the layer itself). Ensure that the mask is white on black, and now select the layer itself. Color that part in. Only the color within the area unmasked by the flame brush will show through.

Here's a very quick and rough example. It's a flame brush, then colored with a yellow-to-red gradient.

Your second image above looks perfctly good, though it is a bit "3d-ish," because of its perfect symmetry. That's not intrinsicly a bad thing, but it depends on the realism you're after,.