Multiply
The Multiply expression takes two inputs, multiplies them together, and outputs the result. When you pass color values as input, the results are similar to the results of the Multiply layer blending mode in Photoshop.
If you pass values with multiple channels, each channel is multiplied separately. For example, if you pass RGB color values to each input, the R channel of the first input is multiplied by the R channel of the second input and the result is stored in the R channel of the output; the G channel of the first input is multiplied by the G channel of the second input and the result is stored in the G channel of the output, and so on.
Both inputs must have the same number of values, unless one of the values is a single float value. In that case, each channel of the multichanneled input is multiplied by the single float value, and stored in a separate channel of the output value.
Item

Description



Const A

Takes in the first value(s) to multiply. Used only if the A input is unused.

Const B

Takes in the second value(s) to multiply. Used only if the B input is unused.



A

Takes in the first value(s) to multiply.

B

Takes in the second value(s) to multiply.

Do not forget that materials in UE4 are not limited to [0,1]. If colors/values are greater than 1, Multiply will actually brighten colors.
Examples: Multiply of 0.4 and 0.5 is 0.2; Multiply of (0.2,0.4,0.6) and (0.0,2.0,1.0) is (0.0,0.8,0.6); Multiply of (0.2,0.4,0.6) and 0.5 is (0.1,0.2,0.3).
Example Usage: Multiply is often used to brighten or darken colors/textures.
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