topic Re: MEL script not working in Maya Forum

MEL script not working

Anonymous — Wed, 13 Dec 2017 21:13:49 GMT

Hey Guys,

I'm having a weird problem with an existing script. I copied and pasted it into MEL, pressed Strg+Enter..so far so good. I also pressed "execute" and now the script is supposed to show up into my scene but it doesnt.

Can anybody tell me what am I doing wrong and can guide me? I also have TeamViewer. just saying

Re: MEL script not working

sean.heasley — Wed, 13 Dec 2017 21:43:39 GMT

Hi @Anonymous and welcome to the community!

Can you please post the script here when you get a chance?

Re: MEL script not working

Anonymous — Wed, 13 Dec 2017 22:19:35 GMT

hi, thanks for replying

proc diamondSquare(float $h)
{
polyPlane -w 1 -h 1 -sx 16 -sy 16 -ax 0 1 0 -cuv 2 -ch 1 -n "terrain";
int $SIZE=16+1;

for ($sidelength = $SIZE-1; $sidelength > 1; $sidelength/=2)
{
int $halfside = $sidelength/2;
for ($x=0; $x<$SIZE-1; $x+=$sidelength)
{
for ($z=0; $z<$SIZE-1; $z+=$sidelength)
{
vector $p0 = `pointPosition -w terrain.vtx[$x + $z*$SIZE]`;
vector $p1 = `pointPosition -w terrain.vtx[$x + $sidelength + $z*$SIZE]`;
vector $p2 = `pointPosition -w terrain.vtx[$x + ($z+$sidelength)*$SIZE]`;
vector $p3 = `pointPosition -w terrain.vtx[$x + $sidelength + ($z+$sidelength)*$SIZE]`;

float $avg = ($p0.y + $p1.y + $p2.y + $p3.y)/4.0;
$r = rand(-1.0*$h, $h);
select -r terrain.vtx[$x+$halfside + ($z+$halfside)*$SIZE];
move -y ($avg + $r);
}
}
for($x=0; $x<$SIZE-1; $x+=$halfside)
{
for($z=($x+$halfside)%$sidelength; $z<$SIZE-1; $z+=$sidelength)
{
vector $p0 = `pointPosition -w terrain.vtx[($x-$halfside+$SIZE-1)%($SIZE-1) + $z*$SIZE]`;
vector $p1 = `pointPosition -w terrain.vtx[($x+$halfside)%($SIZE-1) + $z*$SIZE]`;
vector $p2 = `pointPosition -w terrain.vtx[$x + (($z+$halfside)%($SIZE-1))*$SIZE]`;
vector $p3 = `pointPosition -w terrain.vtx[$x + (($z-$halfside+$SIZE-1)%($SIZE-1))*$SIZE]`;

float $avg = ($p0.y + $p1.y + $p2.y + $p3.y)/4.0;
$r = rand(-1.0*$h, $h);

select -r terrain.vtx[$x + $z*$SIZE];
move -y ($avg + $r);

if ($x == 0)
{
select -r terrain.vtx[$SIZE-1 + $z*$SIZE];
move -y ($avg + $r);
}
if ($z == 0)
{
select -r terrain.vtx[$x + ($SIZE-1)*$SIZE];
move -y ($avg + $r);
}
}
}
$h/=2;
}
}

Re: MEL script not working

Stephen.Blair — Wed, 13 Dec 2017 23:16:05 GMT

That's the proc definition.

To actually use it, you have to execute the proc like this:

diamondSquare( 0.333 );

Re: MEL script not working

sean.heasley — Thu, 14 Dec 2017 15:56:29 GMT

Hi @Anonymous

@Stephen.Blair beat me to it

When you get a chance, can you add the code to yours so we can make sure it works for you as well?

Re: MEL script not working

Anonymous — Thu, 14 Dec 2017 16:36:39 GMT

do i have to add this at the beginning or at the end?

Re: MEL script not working

Stephen.Blair — Thu, 14 Dec 2017 16:44:58 GMT

You can't go wrong by putting it at the end.

1) define proc

2) call proc

That will work in any language.

In MEL, you could call the proc first, because Maya obviously parses the whole thing first.

But in Python, you'd get an error if the definition didn't come first.

Re: MEL script not working

Anonymous — Thu, 14 Dec 2017 16:41:56 GMT

i add this at the very beginning of the script and this is what maya tells me

// Error: Line 51.6: "$h" is an undeclared variable.

Re: MEL script not working

Anonymous — Thu, 14 Dec 2017 16:45:31 GMT

this is very confusing 😕 when i add this at the end

maya tells me that ive to delete this -> $r

// Error: $r = rand(-1.0*$h, $h);
//
// Error: Line 18.18: "$h" is an undeclared variable. //
// Error: $r = rand(-1.0*$h, $h);
//
// Error: Line 18.22: "$h" is an undeclared variable. //
// Error: move -y ($avg + $r);
//
// Error: Line 20.19: "$r" is an undeclared variable. //
// Error: $r = rand(-1.0*$h, $h);
//
// Error: Line 33.18: "$h" is an undeclared variable. //
// Error: $r = rand(-1.0*$h, $h);
//
// Error: Line 33.22: "$h" is an undeclared variable. //
// Error: move -y ($avg + $r);
//
// Error: Line 36.19: "$r" is an undeclared variable. //
// Error: move -y ($avg + $r);
//
// Error: Line 41.19: "$r" is an undeclared variable. //
// Error: move -y ($avg + $r);
//
// Error: Line 46.19: "$r" is an undeclared variable. //
// Error: $h/=2;
//
// Error: Line 50.6: "$h" is an undeclared variable. //

Re: MEL script not working

Stephen.Blair — Thu, 14 Dec 2017 16:46:38 GMT

diamondSquare( .1 );



proc diamondSquare(float $h)
{
polyPlane -w 1 -h 1 -sx 16 -sy 16 -ax 0 1 0 -cuv 2 -ch 1 -n "terrain";
int $SIZE=16+1;

for ($sidelength = $SIZE-1; $sidelength > 1; $sidelength/=2)
{
int $halfside = $sidelength/2;
for ($x=0; $x<$SIZE-1; $x+=$sidelength)
{
for ($z=0; $z<$SIZE-1; $z+=$sidelength)
{
vector $p0 = `pointPosition -w terrain.vtx[$x + $z*$SIZE]`;
vector $p1 = `pointPosition -w terrain.vtx[$x + $sidelength + $z*$SIZE]`;
vector $p2 = `pointPosition -w terrain.vtx[$x + ($z+$sidelength)*$SIZE]`;
vector $p3 = `pointPosition -w terrain.vtx[$x + $sidelength + ($z+$sidelength)*$SIZE]`;

float $avg = ($p0.y + $p1.y + $p2.y + $p3.y)/4.0;
$r = rand(-1.0*$h, $h);
select -r terrain.vtx[$x+$halfside + ($z+$halfside)*$SIZE];
move -y ($avg + $r);
}
}
for($x=0; $x<$SIZE-1; $x+=$halfside)
{
for($z=($x+$halfside)%$sidelength; $z<$SIZE-1; $z+=$sidelength)
{
vector $p0 = `pointPosition -w terrain.vtx[($x-$halfside+$SIZE-1)%($SIZE-1) + $z*$SIZE]`;
vector $p1 = `pointPosition -w terrain.vtx[($x+$halfside)%($SIZE-1) + $z*$SIZE]`;
vector $p2 = `pointPosition -w terrain.vtx[$x + (($z+$halfside)%($SIZE-1))*$SIZE]`;
vector $p3 = `pointPosition -w terrain.vtx[$x + (($z-$halfside+$SIZE-1)%($SIZE-1))*$SIZE]`;

float $avg = ($p0.y + $p1.y + $p2.y + $p3.y)/4.0;
$r = rand(-1.0*$h, $h);

select -r terrain.vtx[$x + $z*$SIZE];
move -y ($avg + $r);

if ($x == 0)
{
select -r terrain.vtx[$SIZE-1 + $z*$SIZE];
move -y ($avg + $r);
}
if ($z == 0)
{
select -r terrain.vtx[$x + ($SIZE-1)*$SIZE];
move -y ($avg + $r);
}
}
}
$h/=2;
}
}

Re: MEL script not working

Anonymous — Thu, 14 Dec 2017 16:49:25 GMT

god bless you

now i have to figure out how to scale the terrain

Re: MEL script not working

Anonymous — Mon, 16 Sep 2019 19:42:17 GMT

If I copy and paste this script or code into the MAYA script editor will anything happen ?