Creating highlights (flares)

[hopbin9]

Hi,

Is it possible to create highlights on the specular bright spots on objects (like small lens flares).

Thanks,

[malexander]

Yep, you can do this with a Limit, a Defocus & an Add COP.

1. Add a Limit COP

1a. Set the lower limit to the lowest hotspot value you want to flare

1b. Disable the upper limit

1c. Change "Clamped Values" to "Replace with Black"

2. Add a defocus COP to the Limit

2a. Play with the defocus size

2b. Play with the Boost factor, threshold and level. Threshold should likely be the hotspot value you entered for the Limit.

3. Add an Add COP

3a. Wire in Defocus

3b. Wire in the input to the Limit COP (the original node).

[hopbin9]

wow, that looks really cool. Thanks

Exactly what I was looking for.

[hopbin9]

Is there a way to scale the defocus based upon depth?

My image source as a Pz channel, but I new to working with channels in DOP.

[malexander]

You'll need to use the Pz image as a mask to the Defocus COP, and turn on "Per Pixel Defocus". But before you add Pz as a mask, you'll need to preprocess it a bit to get in the 0-1 mask range that Defocus expects. Append an Equalize COP to the Pz image, which will maps its near-far range to 0-1. Then a gamma COP will alter the rate at which the defocus effect is applied with respect to depth. Also make sure that the Defocus COP's Mask plane is set to the Pz plane, if that's the name of the depth channel.

[hopbin9]

Thanks, your help has been very valuable.

Need anything, let me know.

[malexander]

Glad to help. Just sing the praises of Houdini, that's all I need