Pit of smoothstep node in shadergraph

ShaderGraph in SmoothStep node , Introduction in the document ：

If input  In  The value of is in the input  Edge1  and  Edge2  Between the values of , return 0 and 1 Between the smooth Hermite interpolation results . If input  In  The value of is less than the input  Step1  Value , return 0; If it's greater than the input  Step2  Value , return 1.

This node is similar to  Lerp node , But there are two significant differences . First , When using this node , User specified range , The return value is between 0 and 1 Between . This can be seen as related to  Lerp node contrary . secondly , This node uses smooth Hermite interpolation , Instead of linear interpolation . This means that the interpolation will gradually speed up from the beginning , And slow down near the end . This is for creating natural animations 、 Fade in, fade out and other transitions are very useful .

Specific reference  Smoothstep node | Shader Graph | 10.5.0

then , I encountered a problem when making case contact

  How does this figure pass through SmoothStep Node to get the gradient bar , After many tests, I got the result , Not necessarily right , Some big guys know the principle , We can discuss .

Pictured above ,edge1 Is the coordinates of the model itself Y value , Values for 0 to 1,edge2 by Offset value , For an externally adjustable threshold （ Control where the black belt appears ）,In The value is Offset Subtract one -0.5 to 0 A value of （ Controls the width of the black band in the graph ）, If you do not change the value , Then only edge1 It is changing. ,edge1 from 0 Change to 1 The process of ,edge1 The value of edge2 near ,edge1 and edge2 The distance is getting smaller and smaller , And because of In The value of is always higher than edge2 A small fixed value （ Width ）, So the final output is getting closer edge1 Of , namely in It changes from white to black （ See the node explanation above , In between , Is from the closer edge1,in Values tend to 0, On the contrary, it tends to 1, And not linear ）, In this case ,edge1 from 0 Change to In Value can explain . From the following figure , After the results are flipped , Obviously , The lower half is gradient , Not solid .

And then there was edge1 Greater than In The value of , That's it In Less than edge1, return 0; Here's the picture , I did the result Step operation , Less than 0.01 Of , This is the part .

 

Then why did it turn white again , This is what I have been thinking about before , He when edge1>edge2 When , He can't form an interval , Greater than edge2 by 1, Less than edge1 by 0, Between the two is 0-1 change , These three cases are combined , There are intersections , There will be less than edge1, More than dege2, What is the result of this situation , After my test , The conclusion is that ,In Value close to which , It is the output value of which to follow , Here's the picture .

  thus , This operation is also fully explained , And the results are consistent with the actual display .