Add Multiplied Scalar explained

Started by Hetzen, September 30, 2019, 08:43:45 am

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Hetzen

September 30, 2019, 08:43:45 am Last Edit: October 14, 2019, 06:24:55 pm by Hetzen
Add Multiplied Scalar will multiple the Main Input with Input 2 and add that result with the Main Input.

Notice this node only looks at Scalar information and ignores any displacement. If the input values are positive, this node will essentially masks Input 2 and add that to the Main Input as you can see in following example.

Add_Multiplied_Scalar_01.jpg

If Input 2 is disconnected, the Main Input passes through to the Output.

Add_Multiplied_Scalar_02.jpg

If the Main Input is disconnected, nothing passes through.

Add_Multiplied_Scalar_03.jpg

This node is a compact way of using an Add Scalar and Multiply Scalar connected in the below example, and can be useful in combining different scales of noise.

Add_Multiplied_Scalar_04.jpg

If there's any errors, omissions or questions about the above, please leave a comment below.

https://planetside.co.uk/wiki/index.php?title=Add_Multiplied_Scalar

WAS

October 14, 2019, 01:37:15 pm #1 Last Edit: October 14, 2019, 01:41:12 pm by WAS
I would like you to expand on this, and clarify some information, please. :) No input is masked. It's multiplied by "black" or 0. The data is still there, especially when worked with unclamped scalars. It's been essentially floored to 0. Additionally, negative unclamped values will be multiplied, as well as values above 1. 
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Hetzen

Thanks Jordan, well spotted. I've corrected the first post to say positive values re-masking.

WAS

October 15, 2019, 01:56:37 pm #3 Last Edit: October 15, 2019, 02:01:43 pm by WAS
Well is information being masked or is it multiplied? Sure it can be used as a mask.

What about the scalar data you are trying to represent? Its chief use is displacement maps (otherwise might as well use Colour functions).

So what about what's actually going on?

What's happening to the data in formula that's representative of mathematics? For example, what about when two locations in both maps contain a value of 0.5 where another has 1, or where both have a value of 1 (or above) and add multiplied? What is the scalar value which would be displacement amplitude?

This post is sorta very basic and just visual, and doesn't correctly cover the function.
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WAS

These are all mainly mathematical functions, and I think that's the main focal area that should be being explained. What's happening with these functions under the hood. Visual results are important, but not that important to what's being done inside, or what the result actually translates too in data.
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Hetzen

Add Multiplied Scalar as in the last image of the first post is a compact way of connecting an Add Scalar with a Multiply Scalar together in the way that's shown. That's all that is going on.

So if you have a value of 0.5 in the Main Input and 1 in Input 2, the maths is:

0.5 x 1 + 0.5 = 1

If the Main Input is -1 and Input 2 is 1:

-1 x 1 + -1 = -2

or with Main Input is -0.5 and Input 2 is 2:

-0.5 x 2 + -0.5 = -1.5

and so on.

If you add vectors or colour into the inputs, there is a conversion that happens to those three component data streams to make a scalar value with one component. I've tried to cover that in Add Scalar and you can find further information in the the wiki here.

Masking (which may have been a descriptive error on my part in the initial post) is essentially multiplying one scalar value with another to hopefully produce an alpha mask of a range of 0 to 1. Black to white.
As you mentioned, you can put in other values which fall out of this range of 0 to 1 depending on the input values.

Oshyan

Posts about the goals and process around the "Functions Nodes in Practice" forum area as a whole have been split into their own discussion.
https://planetside.co.uk/forums/index.php/topic,27174.0.html

Please keep the individual node discussion threads focused on the node in question.

- Oshyan