Math Node Maya with Python script

Coding
1

Hi,
i am using a math node from here https://apps.autodesk.com/MAYA/en/Detail/Index?id=212304226072872821&appLang=en&os=Win64

what i am trying to achieve is to implement this Python script with this math node,
I put here the parenthesis of (a) , (b), (c ) and (result), so these are the equivelant to MathNodes variables and result

import maya.cmds as mc
import math

previous_driver_angle(a) = 0.
previous_driven_angle(b) = 0.

def testFunction():
    global previous_driver_angle, previous_driven_angle

next_driver_angle(c) = mc.getAttr('driver.rotateX')
next_driven_angle(result) = max(math.floor(previous_driven_angle / 60. + 10 ** -6) * 60.,     
previous_driven_angle + (next_driver_angle - previous_driver_angle) * 60. / 55.)
mc.setAttr('driven.rotateZ', next_driven_angle)
previous_driver_angle = next_driver_angle
previous_driven_angle = next_driven_angle

So in the math node i am writing in the Expression tab this:

[(b / 60. + 10 ** -6) * 60., b + (c - a) * 60. / 55.)]
a = 0
b = 0
c =  (driver.rotateX)

I connect driver’s rotate X with c and then i connect the result of MathNode to driven.rotateZ.

And this is the error i get:

// Error: SyntaxError: file
C:/ProgramData/Autodesk/ApplicationPlugins/MathNode/Contents/plug-ins/asdkMathNode.py line 82: invalid syntax //
Expression [(b / 60. + 10 ** -6) * 60., b + (c - a) * 60. / 55.)] failed// Error: SyntaxError: file C:/ProgramData/Autodesk/ApplicationPlugins/MathNode/Contents/plug-ins/asdkMathNode.py line 82: invalid syntax //
Expression [(b / 60. + 10 ** -6) * 60., b + (c - a) * 60. / 55.)] failed

Any idea would be appreciated thank you

2

The trailing closing parentheses doesn’t have a pair (no paired open parentheses).

3

Using a good IDE will help identify issues like these straight away (PyCharm for example).

4

Thank you for your reply i remove the xtra parenthesis now the expression is like this:

 (b / 60. + 10 ** -6) * 60., b + (c - a) * 60. / 55.

but i have this erros now:

// Error: TypeError: file C:/ProgramData/Autodesk/ApplicationPlugins/MathNode/Contents/plug-ins/asdkMathNode.py line 88: in method 'MDataHandle_setFloat', argument 2 of type 'float' //

5

Also when i am trying to add this: max(math.floor to expression it pops an error that math is not defined

6

If you’re getting a NameError that math is not defined then you need to import it.

import math

7

Yes i know
now i get this:
// Error: SyntaxError: file C:/ProgramData/Autodesk/ApplicationPlugins/MathNode/Contents/plug-
ins/asdkMathNode.py line 82: invalid syntax //
Expression import math max(math.floor(b / 60. + 10 ** -6) * 60., b + (c - a) * 60. / 55.) failed

8

Is the import on a separate line?
Without formatting it’s difficult to see what the formatting issue could be…

9

No its not on another line,
it doesnt allow me to press enter in the math node expression slot.
everything is in one line
import math max(math.floor(b / 60. + 10 ** -6) * 60., b + (c - a) * 60. / 55.)

10 
import math
max(
    math.floor(b / 60.0 + 10 ** -6) * 60.0,
    b + (c - a) * 60.0 / 55.0
)
11

If that’s the case you can use semi-colon.
import math;max(math.floor(b / 60. + 10 ** -6) * 60., b + (c - a) * 60. / 55.)
Although I’m not sure this is a good idea. Not at a computer ATM so I can’t suggest an alternative.

12

No worries,
although i still have this error:
Expression import math;max(math.floor(b / 60. + 10 ** -6) * 60., b + (c - a) * 60. / 55.) failed// Error: SyntaxError: file C:/ProgramData/Autodesk/ApplicationPlugins/MathNode/Contents/plug-ins/asdkMathNode.py line 82: invalid syntax //

even with the semicolons

13

Last ditch effort, try with trailing numbers for the floats.
60.0

14

Expression import math;max(math.floor(b / 60.0 + 10 ** -6) * 60.0, b + (c - a) * 60.0 / 55.0) failed// Error: SyntaxError: file C:/ProgramData/Autodesk/ApplicationPlugins/MathNode/Contents/plug-ins/asdkMathNode.py line 82: invalid syntax //

No luck unfortunatelly :frowning:

15

max(((b / 60.0 + 10 ** -6) // 1) * 60.0, b + (c - a) * 60. 0 / 55.0)

Try with the floordiv operator //

16

At the beginning with a fresh node everything works fine.
i even put manually numbers on c attr, (no error).
But, when i connect the result output to a rotate Z of a group lets say, then i have the error syntax.

Expression max(((b / 60.0 + 10 ** -6) // 1) * 60.0, b + (c - a) * 60. 0 / 55.0) failedExpression max(((b / 60.0 + 10 ** -6) // 1) * 60.0, b + (c - a) * 60. 0 / 55.0) failed// Error: SyntaxError: file C:/ProgramData/Autodesk/ApplicationPlugins/MathNode/Contents/plug-ins/asdkMathNode.py line 82: invalid syntax //

17

My mistake, this line is working:
max(((b / 60.+ 10 ** -6) // 1) * 60., b + (c - a) * 60. / 55.)

but when i want to complete the first python script by adding these two lines:
previous_driver_angle = next_driver_angle
previous_driven_angle = next_driven_angle

max(((b / 60.+ 10 ** -6) // 1) * 60., b + (c - a) * 60. / 55.);(a = c); (b= result);

then i have again error syntax

18

The python script and a mel expression are very different things, so you can’t often have a direct translation.
I didn’t pay as much attention to what you were actually trying to solve as I should have, leading to this long thread.

Writing it as an expression should be possible.
I would suggest taking a look at some learning material for writing expressions in Maya otherwise I imagine a significantly longer thread unless the answer is posted :slight_smile:

You should be able to find the previous value through caching, or perhaps getAttr frame -1 (not recommended during expressions as it’ll affect performance).
You should also be able to use the frameCache node to get attr value from a previous frame.

19

Should i use the frame cache node and the Expressions?

20

Using the frameCache node, you should be able to implement with nodes instead of an expression I think?

Once I’m at a computer I’ll be in a much better position to provide something other than semi-thought out advice.
That being said, there are generally much smarter and more experienced people than myself around who might point you in a better direction whilst you wait :slight_smile: