can you render just the bumpmap?

Started by XD1, November 02, 2018, 11:23:29 AM

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INNEO_MWo

Quote from: DMerz III on November 08, 2018, 01:57:05 PM
One of these days, I will do a video tutorial series on my method for condensation on a can. It isn't nearly as good as that photograph you posted, but for a marketing type of image, I think we do pretty darn good for the time and tools we use.

I'd like to see such technique.
So please give us a hint if the tutorial is ready to see.

Thank you, David!

INNEO_MWo

I am sorry about my previous post. I didn't want to annoy anyone.
The water drops or better the space between the drops looks too regular, so I guessed it was a render.

Marco

bdesign

#17
This is not answering your specific question, but is a suggestion for an alternate method of adding the labels in post. While not perfectly, physically correct, I think it is fairly convincing, especially to the "untrained eye". It is quite easy, especially if you will be rendering straight on, near-orthographic camera views such as in your photo reference. Try this: get your condensation looking nice on a blank can, and render. Open the render in Photoshop and add your labels on top of the can, then set the blend mode to Overlay. To get different looks for the label, you can duplicate the label layer and place it below the original Overlay layer, changing the opacity and experimenting with other blend modes (for instance, placing a 30% opacity duplicate below the original and setting the blend mode to Color Burn will give the label a more "metallic" look). As a final subtle detail, you can use Filter > Distort > Displace on the labels, using one of the RGB channels of your normal map as the displacement map (I used the green channel with Horizontal and Vertical Scale values at 1). The example renders below are:

1. Blank can with condensation
2. Can with labels added in PS, blend mode = Overlay
3. Can with labels added in PS, blend mode = Overlay / 30% opacity duplicate below, blend mode = Color Burn
4. Can with labels added in PS, blend mode = Overlay / 30% opacity duplicate below, blend mode = Color Burn, both layers displaced with the normal map green channel, with Horizontal and Vertical Scale values at 1

If rendering camera angles with more perspective, it will take some tweaking in PS to get the labels to match the perspective, but can be done using Edit > Transform > Distort and Edit > Transform > Perspective. For a comparison to this same can/condensation with the labels rendered directly in KeyShot, see here: https://www.keyshot.com/forum/index.php?topic=22691.new#new . (The KeyShot icon label in this render is a metal material with a lower roughness value than the can.)

Cheers,
Eric

mattjgerard

Pretty epic demo there, Eric. The refraction through the water droplets is pretty convincing.

bdesign

Quote from: mattjgerard on November 12, 2018, 06:23:22 AM
Pretty epic demo there, Eric. The refraction through the water droplets is pretty convincing.

Thanks, Matt. Glad you think so :)

Cheers,
Eric

Eugen Fetsch

@jamesp

Hi James,
Hope I understood your request properly.

If you have the base geometry with big ocean waves, like in the image "1.png" ...
and you need to extract a normal pass from it - image "2.png" ...
... then add an additional bump on it - image "3.png" ...
... and like to have the bump information on the normal pass - image "4.png"...

... in this case you need to render 2 times:
- 1x in Product mode to get the normal path from the base geometry
- 1x in Interior mode to get the bumps on the normal path

For the second render you can go with very low samples (8-16), don't go less if you need good Anti Aliasing.

Cheers,
Eugen

Will Gibbons

So, the refraction was faked by using the green channel of the normal map in photoshop? How exactly was the normal map layer interacting with the others to make it look refracted or distorted?

Hopefully the question I'm asking makes sense. I assumed this was possible but hadn't tried it before. Interested to hear if you can share a touch more detail. Let me know if I missed it in your description.

Thanks,

INNEO_MWo

Quote from: bdesign on November 12, 2018, 11:02:36 AM
Quote from: mattjgerard on November 12, 2018, 06:23:22 AM
Pretty epic demo there, Eric. The refraction through the water droplets is pretty convincing.

Thanks, Matt. Glad you think so :)

Cheers,
Eric

Kudos Eric!
You're a CGI ninja!

Cheers
Marco

bdesign

Quote from: MWo on November 13, 2018, 10:09:20 AM
Kudos Eric!
You're a CGI ninja!

Cheers
Marco

Thank you kindly, Marco! Danke schön :)

Cheers,
Eric

bdesign

#24
Quote from: Will Gibbons on November 13, 2018, 09:40:23 AM
So, the refraction was faked by using the green channel of the normal map in photoshop? How exactly was the normal map layer interacting with the others to make it look refracted or distorted?

Hopefully the question I'm asking makes sense. I assumed this was possible but hadn't tried it before. Interested to hear if you can share a touch more detail. Let me know if I missed it in your description.

Thanks,

Yes. The subtle distortion of the labels was done by first rendering the normal map of the can, in Preview Bump mode, then opening in Photoshop and using Split Channels to obtain the RGB and Transparency channels as separate files. I then saved the resulting green channel document as as PSD file to be used as the displacement map on the labels, using Filter > Distort > Displace. You can experiment with different Horizontal and Vertical Scale values, and even run the Displace filter with more than one of the RGB channels, to get more pronounced and/or varied distortions. In the example images below, I've left the label in Normal blend mode to better see the effect of the displace filter.

1. Normal map rendered in Preview Bump mode
2. Green channel used with displace filter
3. Default label on can
4. Displaced label on can

Cheers,
Eric

Will Gibbons

Man, you're a Photoshop wizard. You spend lots of time in it I assume?

Finema

Hi
here a test in keyshot 8 (geometry node) without using photoshop

bdesign

Quote from: Will Gibbons on November 16, 2018, 10:55:04 AM
Man, you're a Photoshop wizard. You spend lots of time in it I assume?

Thanks, Will. I wouldn't say "lots", but I spend a fair amount of time in PS :)

Cheers,
Eric

bdesign

Quote from: Finema on November 16, 2018, 11:59:37 PM
Hi
here a test in keyshot 8 (geometry node) without using photoshop

Nice, Philippe!

Cheers,
Eric

Finema