Soccer balls and Arnold procedurals


I’m partial, but I like the Softimage soccer ball better than the Maya soccer ball.
soccerballs

The Softimage soccer ball is the one on the left. I took the ASS file for the soccer ball, did a few search and replace ops, and compiled my first procedural node. It’s pretty trivial, but it illustrates the basic framework. numNodes() returns the number of nodes you’re going to create; Arnold calls getNode() once for each node you create. I’m just creating one node, so I do it in getNode(), but you could also do it in init().

If you’re interested in learning more about the Arnold SDK and procedurals, you can download the SDK (docs included) at solidangle.com.

#include <ai.h>
#include <string.h>

static int init(AtNode *mynode, void **user_ptr )
{
  AiMsgInfo( "[soccer] -- greetings!" );
  return 1;
}

static int cleanup( void *d )
{
  return 1;
}

static int numNodes( void *d )
{
  return 1;
}

static AtNode *getNode( void *d, int index )
{

	AtByte nsides[540] = {
		4, 4, 4, 4, 4,
		// ...
		4, 4, 4, 4, 4};
  
	unsigned int vidxs[2160] = {
		292, 301, 12, 293, 302, 303, 304, 305, 302, 305, 306,
		//...
		169, 538, 537, 116, 168, 540, 539, 79, 151, 25, 541};

	unsigned int nidxs[2160] = {
		0, 1, 2, 3, 4, 5, 6, 7, 4, 7, 8, 9, 4, 9, 10, 11, 4, 
		// ...
		1211, 1216, 1215, 1230, 1229, 311, 322, 1231, 312};

	float vlist[1626] = {
		2.33102179f, 4.68985701f, -7.74118519f, -4.0108633f, -2.08138514f, 8.18039227f,
		//...
		1.70574367f, 2.03463793f, 9.00535202f, 2.94963598f, 0.0429565944f, 8.85224628f};

	float nlist[3696] = {
		-0.00219265698f, -0.443717808f, -0.896163881f, -0.112498537f, -0.405027777f, -0.907356858f, 
		//...
		-0.316353977f, -0.846433043f, 0.428335458f, 0.514008343f, -0.00765316607f, 0.857751012f};

	AtMatrix m;
	AiM4Identity( m );
	
	AtNode *n = AiNode( "polymesh" );
	AiNodeSetByte(n, "visibility", 255);
	AiNodeSetArray(n, "vlist",  AiArrayConvert(1626,  1, AI_TYPE_FLOAT, vlist));
	AiNodeSetArray(n, "nsides", AiArrayConvert(540,  1, AI_TYPE_BYTE,  nsides));
	AiNodeSetArray(n, "vidxs",  AiArrayConvert(2160,  1, AI_TYPE_UINT,  vidxs));
	AiNodeSetArray(n, "nlist",  AiArrayConvert(3696,  1, AI_TYPE_FLOAT, nlist));
	AiNodeSetArray(n, "nidxs",  AiArrayConvert(2160,  1, AI_TYPE_UINT,  vidxs));
//	AiNodeSetArray(n, "uvidxs", AiArrayConvert(384,  1, AI_TYPE_UINT,  uvidxs));
//	AiNodeSetArray(n, "uvlist", AiArrayConvert(270,  1, AI_TYPE_FLOAT, uvlist));

	AiNodeSetMatrix(n, "matrix", m );

	AiNodeSetStr(n, "name", "SISoccerBall");
	return n;
};



// --------------------------------------------------------------------------------
// dso hook.
// --------------------------------------------------------------------------------
proc_loader
{
  vtable->Init     = init;
  vtable->Cleanup  = cleanup;
  vtable->NumNodes = numNodes;
  vtable->GetNode  = getNode;
  strcpy_s(vtable->version, AI_VERSION);
  return 1;
}

One thought on “Soccer balls and Arnold procedurals

  1. Hi, I am new to the Arnold API, is there any good documentation on how to use the API, like an example on how to setup and use it. In the documentation they just describe all the available options but there is no proper example for any of them. It would be great if you could explain ! Thank you very much.

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