Sunday, November 8, 2009

House Of Stairs

English    Spanish

Today I'm going to show a set of renders that although they are not totally finished I would like to show.
The target is the representation in 3D of the picture "House Of Stairs" of M.C.Escher. I focused the representation of walls and stairs. The strange animals and the doors are missing.

The results are these, in black and white and in color:


In the color version I have simply used blackbody illuminants with temperatures of 3000, 4000, 5000 and 7000 Kelvin.

In order to make the renders we have to do this. It's necessary to model the scenery in such a way so the dimensions fit using whole units (fitting into a grid). So we make sure that all walls, walkways and stairs have similar widths. With any CAD program it's possible to model the scenery looking the original drawing. The objects at this point have box geometry.



Because the rendering of boxes is too dull we have to add some effects. One of those has to emulate the round shape of a stone. In order to achieve that we can use textures or 3D models. In this case I preferred using 3D models to achieve more quality. Accomplishing this is simple. We cubicate the scene with the same resolution of the design grid. Now we have a set of voxels. Each voxel is replaced by a rounded cube mesh shape. The only problem is the amount of data and so the high processing time.



Later we apply a material to the surface. For that is used a composite material. The material is composed by one control map and two data maps. The control material is used to decide the amount of blending between the data materials. It's similar to an alpha blending. For the control map I have used a binary threshold discretized Perlin noise function. In the high part I have assigned one kind of bumpmap and in the lowest part another kind. So, two bumpmaps of controllable independent characteristics are obtained. Now we simply apply a greater scale factor and noise to one to look like holes in stone, while applying a smoother noise to the other. With only one bumpmap would have achieved a smoothed and polished stone effect with some holes. We don't want it.



Finally to render it's used a cylindrical camera to emulate the curved effect of "The House of Stairs". With a little wise we can place the camera more or less the same position where Escher sat it.

Monday, September 14, 2009

Spatial Labyrinths

English    Spanish

Today I'm going to show a set of renders that I did some time ago. The general idea is to make a spatial maze.

That is, one that allows movements upwards and downwards as well as forward, backward, right and left. The movements that a player can do are in any spatial axis. In this case, Theseus has to know how to climb well.

One simple is this one:



In this one we see a tridimensional labyrinth bounded by the surface of a cube.

The procedure to accomplish this renders is not complex.
  • We start from a tridimensional shape. Then it's discretized in voxels marking as active the ones that are partially or totally included in the volume defined by the surface of the figure.
  • Now we are going to discard the non active voxels and we work with the ones that intersect or are included inside the volume.
  • We start from a random voxel and we move in a random direction, marking as visited the currant voxel.
  • As we move through the voxels we can find a visited voxel in the chosen direction. In this case we chose another direction.
  • In the case that there are not any available directions we move backwards and we chose another direction.
  • The algorithm ends when all the nodes (voxels) have been visited.
This algorithm allows a unique path from one point of the labyrinth to another. Obviously if we set two poins, one as starting and another one as ending, there will be a unique path between both, and then any other bifurcation that moves away from the path will bring us to a dead end.

Other views of the cube:











It's possible to use other figures as a "mould" of the labyrinth.

Here we can see a sphere:





And with a spherical camera:





The Utah teapot:



and a some renderings of a lying woman: