Processing 1.0 - Processing Discourse

elout

Save as 3ds
Jul 28^th, 2007, 2:36pm

I just started working on a 3ds filesaver, so the 3D model I created in processing can be saved as 3ds, then imported into wings3D or Google earth sketchup etc.

Found information on the 3ds file format on
http://www.wotsit.org/

There seem to be lot of opensource written 3ds loaders, but could not find any 3ds saver yet.

My first attempts will be saving a triangle.

-Work in Progress- update #0.4

-edit- working code is posted now below -edit-

This is the first time I'm using the saveBytes routine, and stuff I still got to figure out is like how to convert the word(2 bytes) and floats (4 bytes) and calculating the chunk length.

« Last Edit: Jul 29^th, 2007, 2:57pm by elout »

V Senior Member Offline Posts: 430 portugal	Re: Save as 3ds Reply #1 - Jul 28^th, 2007, 3:23pm elout, if you have 3dsmax, check the sdk it has a 3ds imp/exp along with others like .ase you might find it very helpful
	Victor Martins \| www.pixelnerve.com/v

elout

Re: Save as 3ds
Reply #2 - Jul 28^th, 2007, 4:52pm

I don't have 3Dmax and using Wings3D and a hex-editor at the moment to analyze the 3ds files. For me it's important to save a 3ds file created in processing.

Just figured out how the ox4110 chunk works.
Still gotta lookup how I can split a float into 4 different bytes, or a word into 2 different bytes.
And ofcourse get the other chunks working.

« Last Edit: Jul 29^th, 2007, 1:07am by elout »

V Senior Member Offline Posts: 430 portugal	Re: Save as 3ds Reply #3 - Jul 28^th, 2007, 6:06pm why split a float into 4 bytes ?
	Victor Martins \| www.pixelnerve.com/v

elout YaBB Newbies Offline Posts: 12	Re: Save as 3ds Reply #4 - Jul 28^th, 2007, 6:55pm Updated: wings crashed on this 3ds file, and sketchup cant load it eather, anyway still fiddeling with it, maybe will add more information like objectname etc. Crmx > I use the saveBytes routine, so somehow I got to convert a float into 4 seperate bytes in this array.

fry

Re: Save as 3ds
Reply #5 - Jul 29^th, 2007, 1:55am

for this situation, i'd recommend using java's DataOutputStream class rather than saveBytes. it'll mean a lot less maintenance along the way because you can just write the file linearly. it would go something like this:

String path = savePath("filename.3ds");
FileOutputStream fos = new FileOutputStream(path);

then you'd use fos.writeInt() or fos.writeFloat() to write individual bits of info.

elout

Re: Save as 3ds
Reply #6 - Jul 29^th, 2007, 2:37pm

Simple 3ds saver - Version #0.7
Saves 2 triangles now you can upload in wings3D or sketchup etc.

I split it up in 2 parts, since the message will be too big, and cant post it then on the forum

--------------------------Part 1--------------------
Code:


// simple .3ds saver - Elout de Kok 2007 -  update #7
// info on  3ds fileformat -  http://www.wotsit.org/list.asp?fc=2

void setup() 
{
  save3ds();
  println("saved the 3ds-file");
}

void save3ds()
{
  int number_of_points=4;
  int number_of_triangles=2;
  
  float [] xyzpoints = {-10.0f,-5.0f,1.0f,   10.0f,-5.0f,1.0f,   1.0f,10.0f,1.0f,   -1.0f, -4.0f, -10.0f};  
  int [] vertexes = {0,1,2, 1,3,2};
  
  
  int [] mesh_version = {0x3D3E, 0x000A, 0x0000,0x0003,0x0000,0xAFFF,0x0080, 0x0000, 0xA000, 0x000E, 0x0000, 0x6564, 0x6166,0x6C75, 0x0074, 0xA030, 0x0018, 0x0000, 0x0011, 0x0009, 0x0000, 0xFFFF, 0x12FF, 0x0900, 0x0000, 0xFF00, 0xFFFF, 0xA040, 0x000E, 0x0000, 0x0030, 0x0008, 0x0000, 0x0000, 0xA020, 0x0018, 0x0000, 0x0011, 0x0009, 0x0000, 0xFFFF, 0x12FF, 0x0900, 0x0000, 0xFF00, 0xFFFF, 0xA050, 0x000E, 0x0000, 0x0030, 0x0008, 0x0000, 0x0000, 0xA010, 0x0018, 0x0000, 0x0011, 0x0009, 0x0000, 0xFFFF, 0x12FF, 0x0900, 0x0000, 0xFF00, 0xFFFF, 0xA100, 0x0008, 0x0000, 0x0003, 0x0100, 0x000A, 0x0000, 0x0000, 0x3F80};
  int [] chunk_4160 = {0x4160, 0x0036, 0x0000, 0x0000, 0x3F80, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x3F80, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x3F80, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000};
    
  int totalbytes=   
			  6					  // 0x4D4D Main chunk
			  +10					// header data
			  +148				     // 0x3D3E Mesh version
			  + 6					// 0x3D3D 3D editor chunk
			  + 6					// 0x4000 Object block (with name of your object)
			  + 6					// name
			  + 6					// 0x4100 Triangular mesh  
			  + 54				     // 4160 matrix chunk
			  + ((number_of_points*3)*4)+4+4   // ox4110 points 44
			  + ((number_of_triangles*8)+4+4)  // ox4120 faces 16
			  + 16 + (number_of_triangles*2)   // 4130 material
			  + 6+(number_of_triangles*4);     // 4150 smoothing groups
  
  byte[] nums = new byte[totalbytes]; // for the moment
  
  int step=0;  
  
  writeshort(nums, step, (short) 0x4D4D); step+=2;     //main chunk 
  writeshort(nums, step, (short) totalbytes); step+=2; //size of next chunks
  writeshort(nums, step, (short) 0); step+=2;
  
  writeshort(nums, step, (short) 0x0002); step+=2;  // header data
  writeshort(nums, step, (short) 0x000A); step+=2;
  writeshort(nums, step, (short) 0x0000); step+=2;
  writeshort(nums, step, (short) 0x0003); step+=2;
  writeshort(nums, step, (short) 0x0000 ); step+=2;
  
  writeshort(nums, step, (short) 0x3D3D); step+=2;	    //3D editor chunk 
  writeshort(nums, step, (short) (totalbytes-16) ); step+=2; //size of next chunks
  writeshort(nums, step, (short) 0); step+=2;

  for (int i=0;i<mesh_version.length;i++)
  {
    writeshort(nums, step, (short) mesh_version[i]); step+=2;   //0x3D3E Mesh version
  }  
  
  writeshort(nums, step, (short) 0x4000); step+=2;	    //Object block chunk
  writeshort(nums, step, (short) (totalbytes-170) ); step+=2; //size of next chunks
  writeshort(nums, step, (short) 0); step+=2;
  
  writeshort(nums, step, (short) 0x7563); step+=2; //write name
  writeshort(nums, step, (short) 0x6562); step+=2;
  writeshort(nums, step, (short) 0x0031); step+=2;

elout

Re: Save as 3ds
Reply #7 - Jul 29^th, 2007, 2:37pm

--------------------------Part 2--------------------
Code:



  writeshort(nums, step, (short) 0x4100); step+=2;	    //Triangular mesh chunk
  writeshort(nums, step, (short) (totalbytes-182) ); step+=2; //size of next chunks
  writeshort(nums, step, (short) 0); step+=2;
  
  for (int i=0;i<chunk_4160.length;i++)
  {
    writeshort(nums, step, (short) chunk_4160[i]); step+=2;   //0x4160 matrix chunk
  }
  
  writeshort(nums, step, (short) 0x4110); step+=2;	    //Vertices chunk
	     
  int vertice_blocksize=((number_of_points*3)*4)+4+4; //((3*xyz)*float_4bytes)  +no of points = 36 + 4 + 4 == 44  
  
  writeshort(nums, step, (short) vertice_blocksize); step+=2;  //Vertices chunk
  writeshort(nums, step, (short) 0); step+=2;  
  writeshort(nums, step, (short) number_of_points); step+=2;  // no of points
    
  int pointstep=0;
  for (int i=0;i<number_of_points;i++)
  {
    writefloat(nums, step, xyzpoints[pointstep++]); step+=4; // x 
    writefloat(nums, step, xyzpoints[pointstep++]); step+=4; // y
    writefloat(nums, step, xyzpoints[pointstep++]); step+=4; // z 
  }

  writeshort(nums, step, (short) 0x4120); step+=2;	    //Faces chunk
  
  int face_chunksize = (number_of_triangles*8)+4+4   +(16+(number_of_triangles*2))+ (6+(number_of_triangles*4));
  
  writeshort(nums, step, (short) face_chunksize); step+=2;	    // chunk block size
  writeshort(nums, step, (short) 0); step+=2;
  writeshort(nums, step, (short) number_of_triangles); step+=2; // number of triangles

  int vertexpos=0;
  for (int i=0;i<number_of_triangles;i++)
  {
    writeshort(nums, step, (short)vertexes[vertexpos++]); step+=2;//1st triangle
    writeshort(nums, step, (short)vertexes[vertexpos++]); step+=2;//2nd triangle
    writeshort(nums, step, (short)vertexes[vertexpos++]); step+=2;//3nd triangle
    writeshort(nums, step, (short)0x0007); step+=2;//flags: all visible
  }
  
  writeshort(nums, step, (short) 0x4130); step+=2; //Faces material list
  writeshort(nums, step, (short) (16+(number_of_triangles*2)) ); step+=2; //size of chunk
  writeshort(nums, step, (short) 0x0000); step+=2;
  writeshort(nums, step, (short) 0x6564); step+=2;
  writeshort(nums, step, (short) 0x6166); step+=2;
  writeshort(nums, step, (short) 0x6C75); step+=2;
  writeshort(nums, step, (short) 0x0074); step+=2;
  writeshort(nums, step, (short) number_of_triangles); step+=2; // number of faces
  for (int i=0;i<number_of_triangles;i++)
  {  
    writeshort(nums, step, (short) i); step+=2;
  }

  writeshort(nums, step, (short) 0x4150); step+=2; // Smoothing groups
  writeshort(nums, step, (short) (6+(number_of_triangles*4)) ); step+=2; // size of chunk
  writeshort(nums, step, (short) 0x0000); step+=2;
    
  for (int i=0;i<number_of_triangles;i++)
  {  
    writeshort(nums, step, (short) 0x0001); step+=2;
    writeshort(nums, step, (short) 0x0000); step+=2;
  }
  
  saveBytes("Test01.3ds", nums);  // save file
  
}

void writeshort(byte output[], int position, short value)
{
  byte b1 = (byte) (value & 0xff);
  byte b2 = (byte) ((value >> 8) & 0xff);
  output[position]=b1;
  output[position+1]=b2;
}

void writefloat(byte output[], int position, float value)
{
  int float_to_int=Float.floatToIntBits(value);
  byte b1 = (byte) (float_to_int & 0xff);
  byte b2 = (byte) ((float_to_int >> 8) & 0xff);
  byte b3 = (byte) ((float_to_int >> 16) & 0xff);
  byte b4 = (byte) ((float_to_int >> 24) & 0xff);
  output[position]=b1;
  output[position+1]=b2;
  output[position+2]=b3;
  output[position+3]=b4;
}

elout YaBB Newbies Offline Posts: 12	Re: Save as 3ds Reply #8 - Jul 29^th, 2007, 2:47pm Thanks for the tips, and Fry I tried DataOutputStream, but somehow saving short or floats. Resulted that they shown at wrong place in the 3ds data. Like 0000 ffff <-instead of-> ffff 0000

fry

Re: Save as 3ds
Reply #9 - Jul 29^th, 2007, 6:36pm

ah, that's an endian issue.. java uses motorola or "network" byte ordering, as opposed to intel/x86 byte order that has things flipped around backwards. to fix this you can find a "little endian" version of dataoutputstream on the net.

...or you can use the saveBytes() model, it's just that it's less fun when you have to do that much work to babysit the byte placement into the array.

elout

Re: Save as 3ds
Reply #10 - Jul 29^th, 2007, 10:17pm

Well I'm glad I got it somehow to work now, but next will be saving more complex 3d models with 1000th+ of points and X ammount of faces, and hope it it still works. but that's more a thing for tommorow, and not today.

I used a hex editor, to explore the different chunks/3D models and data, saved by wings3d, not sure several chunks can be left out. But for me it was important to succesfull load the model in google-sketchup and wings3D the same time, without a crash or error message.

JohnG Ex Member	Re: Save as 3ds Reply #11 - Jul 30^th, 2007, 1:22am If you're looking to load into Wings3D, then .obj will be much much easier, since it's plain text.

elout YaBB Newbies Offline Posts: 12	Re: Save as 3ds Reply #12 - Jul 30^th, 2007, 3:09am For me the main focus was saving it as 3ds; so google sketchup users can import 3D-models I created with processing.

davbol

Re: Save as 3ds
Reply #13 - Jul 31^st, 2007, 12:13am

elout wrote on Jul 30^th, 2007, 3:09am:

For me the main focus was saving it as 3ds; so google sketchup users can import 3D-models I created with processing.

If SketchUp, then why not use DXF The included library does work, and SketchUp will load those DXF's without error. If you're bothered by the difference in coordinate systems you can try this modified version instead: http://www.davebollinger.com/works/p5/rawdxf_rhzu/

It should also work well for 3dsMax, for example: http://www.flickr.com/photos/davebollinger/877869639/

elout YaBB Newbies Offline Posts: 12	Re: Save as 3ds Reply #14 - Aug 5^th, 2007, 1:08am Thanks Davbol for the tip, to be honest never worked with dxf before, and it seems to work even better/easier.