02-14-2023, 06:34 AM
(This post was last modified: 02-14-2023, 07:15 AM by checkpoint10.)
I was playing around with ChatGPT and decided to feed it Pavel's instructions for making a .3D file. Here's what it said:
ChatGPT: "This is a set of instructions for creating a 3D file, consisting of points, polygons, and a BSP tree. The file must begin with the string "3D VERSION 3.0;" and all strings must be ended with ";". All comments can be placed after "%". A "nil" pointer is represented by "NIL;". In the BSP tree, polygons must be arranged in reverse order from the driving direction. The forms for creating polygons include "POLY" and "FACE". "MATERIAL" is used to assign a texture to a polygon. "DYNAMIC" is used to create a dynamic object."
Me: "Create an example of a 3D file based on the above instructions."
ChatGPT:
ChatGPT: "This creates a simple house object with five polygons for the front, back, right, left, and top sides, and assigns texture materials to each polygon. The BSP tree is constructed by linking the polygons in the correct order to create a 3D object that can be rendered by a game engine."
Me: "Can you explain how a BSP tree works? I'm struggling to understand it."
ChatGPT: "A BSP (Binary Space Partitioning) tree is a hierarchical data structure used in computer graphics to efficiently render complex 3D scenes. The basic idea of a BSP tree is to recursively split a scene into two parts based on the position of objects in the scene. Each split is defined by a plane, which is chosen to divide the scene in such a way that the resulting parts contain roughly equal numbers of objects.
At the top of the tree is the root node, which represents the entire scene. The root node is split into two child nodes based on a chosen plane. Each of these child nodes can then be split further, and the process continues until every object in the scene is contained in a leaf node of the tree.
When rendering a scene using a BSP tree, the tree is traversed in a depth-first order, and objects are drawn in the order in which they are encountered. This ensures that objects that are closer to the viewer are drawn last, and therefore appear on top of objects that are farther away.
One of the key benefits of using a BSP tree is that it can greatly reduce the number of objects that need to be rendered, which can lead to significant performance improvements. Additionally, BSP trees can be used to perform efficient collision detection in games and other interactive applications."
Second example. I just gave it the following code, which is Pavel's example for making a grandstand:
And with no further explanation from me (and this is a separate conversation from the one above, so it doesn't have Pavel's instructions for it), ChatGPT said:
This appears to be a code snippet written in a programming language used for 3D modeling. It defines a set of points and polygons, and creates a BSP tree to represent the geometry of a 3D object. The object appears to be a seating area or stadium, with different sections and viewpoints. The last line of code creates a switch to control the level of detail based on the viewer's distance from the object.
ChatGPT: "This is a set of instructions for creating a 3D file, consisting of points, polygons, and a BSP tree. The file must begin with the string "3D VERSION 3.0;" and all strings must be ended with ";". All comments can be placed after "%". A "nil" pointer is represented by "NIL;". In the BSP tree, polygons must be arranged in reverse order from the driving direction. The forms for creating polygons include "POLY" and "FACE". "MATERIAL" is used to assign a texture to a polygon. "DYNAMIC" is used to create a dynamic object."
Me: "Create an example of a 3D file based on the above instructions."
ChatGPT:
Code:
3D VERSION 3.0;
% USER DEFINED POINTS
% front side of a house
point0001: [<0, 0, 0>];
point0002: [<0, 0, 10>];
point0003: [<5, 0, 10>];
point0004: [<5, 0, 0>];
point0005: [<0, 5, 0>];
point0006: [<0, 5, 10>];
point0007: [<5, 5, 10>];
point0008: [<5, 5, 0>];
% POLYGONS
front: POLY [T] <42> {point0001, point0002, point0003, point0004};
back: POLY [T] <41> {point0005, point0006, point0007, point0008};
right: POLY [T] <43> {point0004, point0003, point0007, point0008};
left: POLY [T] <44> {point0001, point0005, point0006, point0002};
top: POLY [T] <45> {point0005, point0006, point0007, point0008, point0004, point0003, point0002, point0001};
front01: MATERIAL MIP="wall01", GROUP=3, front;
back01: MATERIAL MIP="wall01", GROUP=3, back;
right01: MATERIAL MIP="wall02", GROUP=3, right;
left01: MATERIAL MIP="wall02", GROUP=3, left;
top01: MATERIAL MIP="roof01", GROUP=3, top;
% BSP TREE
front_bsp: BSPF (point0001, point0002, point0003), NIL, back_bsp, right_bsp;
back_bsp: BSPF (point0005, point0006, point0007), NIL, left_bsp, front_bsp;
right_bsp: BSPF (point0004, point0003, point0007), front_bsp, top_bsp, NIL;
left_bsp: BSPF (point0001, point0005, point0006), back_bsp, NIL, top_bsp;
top_bsp: FACE2 (point0001, point0002, point0003), right_bsp, left_bsp;
ChatGPT: "This creates a simple house object with five polygons for the front, back, right, left, and top sides, and assigns texture materials to each polygon. The BSP tree is constructed by linking the polygons in the correct order to create a 3D object that can be rendered by a game engine."
Me: "Can you explain how a BSP tree works? I'm struggling to understand it."
ChatGPT: "A BSP (Binary Space Partitioning) tree is a hierarchical data structure used in computer graphics to efficiently render complex 3D scenes. The basic idea of a BSP tree is to recursively split a scene into two parts based on the position of objects in the scene. Each split is defined by a plane, which is chosen to divide the scene in such a way that the resulting parts contain roughly equal numbers of objects.
At the top of the tree is the root node, which represents the entire scene. The root node is split into two child nodes based on a chosen plane. Each of these child nodes can then be split further, and the process continues until every object in the scene is contained in a leaf node of the tree.
When rendering a scene using a BSP tree, the tree is traversed in a depth-first order, and objects are drawn in the order in which they are encountered. This ensures that objects that are closer to the viewer are drawn last, and therefore appear on top of objects that are farther away.
One of the key benefits of using a BSP tree is that it can greatly reduce the number of objects that need to be rendered, which can lead to significant performance improvements. Additionally, BSP trees can be used to perform efficient collision detection in games and other interactive applications."
Second example. I just gave it the following code, which is Pavel's example for making a grandstand:
Code:
3D VERSION 3.0;
% USER DEFINED POINTS
% side left
point0001: [< -360000, 250000, 190000>, T=<116, 143>];
point0002: [< -360000, 250000, 0>, T=<116, 208>];
point0003: [< -360000, 0, 0>, T=<33, 208>];
point0004: [< -360000, 0, 70000>, T=<33, 187>];
% grand seats
point0005: [< -360000, 250000, 190000>, T=<3, 0>];
point0006: [< -360000, 0, 70000>, T=<3, 63>];
point0007: [< 360000, 0, 70000>, T=<175, 63>];
point0008: [< 360000, 250000, 190000>, T=<175, 0>];
% front grand
point0009: [< -360000, 0, 70000>, T=<0, 215>];
point0010: [< -360000, 0, 0>, T=<0, 248>];
point0011: [< 360000, 0, 0>, T=<255, 248>];
point0012: [< 360000, 0, 70000>, T=<255, 215>];
% side right
point0013: [< 360000, 250000, 190000>, T=<116, 143>];
point0014: [< 360000, 250000, 0>, T=<116, 208>];
point0015: [< 360000, 0, 0>, T=<33, 208>];
point0016: [< 360000, 0, 70000>, T=<33, 187>];
% POLYGONS
sidel: POLY [T] <41> {point0001, point0002, point0003, point0004};
grand: POLY [T] <45> {point0005, point0006, point0007, point0008};
front: POLY [T] <37> {point0009, point0010, point0011, point0012};
sider: POLY [T] <40> {point0016, point0015, point0014, point0013};
% BSP TREE
nil: NIL;
sidel01: MATERIAL MIP="page04", GROUP=3, sidel;
_Sl: BSPF (point0001, point0002, point0003), nil, sidel01, nil;
grand01: MATERIAL MIP="grand1", GROUP=3, grand;
_G: BSPF (point0005, point0006, point0007), nil, grand01, _Sl;
front01: MATERIAL MIP="page04", GROUP=3, front;
_F: BSPF (point0009, point0010, point0011), nil, front01, _G;
sider01: MATERIAL MIP="page04", GROUP=3, sider;
hi: BSPF (point0016, point0015, point0014), nil, sider01, _F;
COOL: SWITCH DISTANCE (point0016) > {(2500000 ? hi), (750000 ? hi), (0 ? hi)};
And with no further explanation from me (and this is a separate conversation from the one above, so it doesn't have Pavel's instructions for it), ChatGPT said:
This appears to be a code snippet written in a programming language used for 3D modeling. It defines a set of points and polygons, and creates a BSP tree to represent the geometry of a 3D object. The object appears to be a seating area or stadium, with different sections and viewpoints. The last line of code creates a switch to control the level of detail based on the viewer's distance from the object.