Lighting Workshops Week 3

 Post Processing

    We'll be taking a look at LUTs now. LUTs stand for color 'Lookup Table'. They're useful for adding color corrections in a post process volume. 

    This is the neutral LUT that unreal gives you in its documentation here.  You can take this into photoshop, apply several filters to it, and then export it back into Unreal. 

    Get a screenshot from your scene. Save it and bring it into photoshop (or any other photo editing program). You can apply any color adjusting layer that controls the overall color. 

    

    Once you're happy with the color adjustments, group all your layer adjustments, and copy this into a new file with the basic LUT image. Now your color adjustments are applied to the LUT. Export this out. (You can export out a PNG, TIFF, etc)

    Bringing it into Unreal, open the texture settings for it. Change the Texture Group of the LUT as 'ColorLookupTable'. If you don't do this step the colors will look off. 

    Select your post process filter, go down into Color Grading to find the Color Grading LUT option. 

    Apply the LUT and you should see the exact same colors that were in photoshop. 

Thursday Notes

Notes on Product Shots: When you want to light a product, the problem with lights are that they are additive. You want to show the actual color of the product or else it will be misleading. One of the techniques used is to mainly use Rim lights to separate it from the background, leave the intensity of the key low. 

    If you need to push the foreground out from the background, use a Rim light. 

Lighting the Car quick example

    Steps taken: 

• got the car mode Cutlass, make sure its in your content folder under Cars>Cutlass
• Bring in all the models, you'll need to assign the materials to the car now, select them all. (the new materials are in the textures folder given)

• bring in a plane for the ground and several cubes for the background, for the materials we went onto fab and got a concrete plaster material and a shiny concrete material. 

• Use the environment light mixer window to bring in all the basic environment lights. 

• adding the spec: 

no spec

nice line spec

•     Take a point light, then increase the source length so its a long skinny cylinder. This elongates the specular into a line. You can also control what light effects what objects using the light channels
• There's currently only 3 channels and You'll have to change which ones are affecting which

default is that all lights are in channel 0

 

You also have to adjust the light channels on the object as well. The car is affected by channel 0 and 1

Point light only affecting the car in channel 1

Point light affecting channel 0 with everything else in it