Interpolative maths for splines

Behold! An insanely in-depth and generous investigation/documentation on spline math! 

 https://pomax.github.io/bezierinfo/#pointvectors3d

 

And to go with it, a spline rigging component!

https://github.com/blurstudio/TwistSpline 

Sin Expressions

 So it finally happened, the URL that I used for 15+ years to reference sin math went down.

For posterity, i'll paste it here:

Fun with Sin


To create the sine wave curve pictured in the first example below, consider the illustration above. Imagine the hypotenuse, C, of the triangle sweeping around the circle in a counter-clockwise rotation. At each point along the sweep, you get back the length of A on the Y axis. The circle is 1 unit in radius, so the value goes from 0 to 1, then back to 0, then 0 to -1 and back to 0 again.The reason you get the "sine wave" curve below is that you are progressing through the values of the 'sweep' over time.

The sin() function uses as its input the angle, , of the counter-clockwise 'sweep', in radians, not degrees.
There are 2* PI radians in 360 degrees.
radians = degrees * (PI / 180)
degrees = radians * (180 / PI)
More easily, in MEL you can convert using the commands "deg_to_rad" and "rad_to_deg".

In these examples, Maya's predefined attribute called "time" (the current time in seconds) is input to the sin function. This means at 3.1415927 seconds, we've gone 180 degrees around the circle, which gives the progression from 0 to 1 and back to 0. At 6.28 seconds we are the rest of the way around (0 to -1 to 0) and the cycle repeats.

Note: the curves graphed below are the result of baking the expressions into keyframes. You won't see these curves in the graph editor when using expressions.

function	description	example
sin( )	returns the sine of the given value. The sine ratio is a value between -1 and 1. With a steadily increasing or decreasing argument, the cos function returns steadily increasing or decreasing values between -1 and 1. This is useful for creating rhythmic, oscillating changes in attribute values.	translateY = sin(time); you can change the frequency of the sine wave: translateY = sin(time*5); you can change the amplitude: translateY = sin(time) * 2; and offset the value: translateY = sin(time) + 6; or use all in one expression: translateY = (sin(time * frequencyMultiplier) * amplitude) + offset;
cos( )	The cosine ratio is a value between -1 and 1. The cos function works like the sin function except its return values are 90 degrees, or pi/2, out of phase.	translateY = cos(time); The cos function is very handy for making an "opposing" action to an object being controlled by the sin function.
abs( )	Returns the absolute value of number. The absolute value of an integer or floating point number is the number without its positive or negative sign. The absolute value of a vector is a vector with components stripped of negative signs.	translateY = abs( sin(time) ); the absolute value of the sine wave makes for a good bouncing action.
max( )	Returns the larger of two floating point numbers. float max(float number, float number) number is a number you want to compare.	translateY = max( 0, sin(time) ); max works like a clamp. The sine wave is not allowed to go below 0.
min( )	Returns the lesser of two floating point numbers. float min( float number, float number) number is a number you want to compare.	translateY = min( 0, sin(time) ); The sine wave is not allowed to go above 0. Consider also you can use min and max combined together for some uses that need clipping on both high and low values: translateY = min( 0.5, max( 0, sin(time) ) );
linstep( )	Returns a value from 0 to 1 that represents a parameter's proportional distance between a minimum and maximum value. This function lets you increase an attribute such as opacity from 0 to 1 linearly over a time range. float linstep(float start, float end, float parameter) start and end specifies the minimum and maximum values. parameter is the value you want to use to generate the proportional number. If parameter is less than start, linstep returns 0. If parameter is greater than end, linstep returns 1.	translateY = linstep( 0, 1, sin(time) ); The result is very similar to "max" above, but keep in mind that the first two values are the upper and lower 'thresholds' that are allowable, and when one or the other is reached, the output is limited between 0 and 1 ONLY. For example: translateY = linstep( 0, 0.25, sin(time) );

VsCode - auto path completion/autocompletion

The Problem: 

For a while it haunted me that my custom repos/packages weren't auto-completing, not ctrl+mouse hover to see what a function did.

 The Fix:

F1 > Preferences: Open Workspace Settings (JSON)

 

Ensure you have "settings", if not, add it.

Ensure you have "python.analysis.extraPaths" : ["your paths here"], if not, add it. 

    "settings": {

        "git.ignoreLimitWarning": true,

        "python.analysis.extraPaths": [

            "C:\\Users\\a_tav\\3D work and portfolio\\AT_autorig",

            "C:\\Users\\a_tav\\3D work and portfolio\\scripts",

            "C:\\Users\\a_tav\\3D work and portfolio"

        ],

        "python.analysis.autoImportCompletions": true,

        "python.analysis.completeFunctionParens": true,

        "python.analysis.useLibraryCodeForTypes": true,

        "editor.definitionLinkOpensInPeek": true,

        "files.associations": {

            "random": "cpp"

        },

 

Selecting a mesh selects the shape, not the transform

 Here's a weird one...

The Problem:

When I select a mesh/curve, it selects the shape - not the transform!

The Fix:

Turn off 'Enable Overrides' of the shape. Normally transforms are part of display layers, and when an object is added to a display layer, it links the display layer 'Display Type' to the objects 'Display Type'. However, adding a transform does not add the shape. Therefore, if you have a Display Layer set to reference, you may still be able to select a layer object's shape if 'Enabled overrides' on the shape is turned on and set to 'Normal'. 

Models grey in viewport

The Problem:

My models are grey in the Maya viewport, even though they have a material with colour assigned!

The Fix:

At the top of the viewport window...:

Shading > Use Default Material (uncheck)