Inside Customization

Inside Customization

Terminology Key
The Sims Community 3D Community
3D model or mesh Object
Objects (2D Renders) Renders of Props
Skins Textures
(Head or Body)
Characters (3D models)
(Hats, Scarfs, Glasses etc.)
Character Accessories
P-Sprites Renders on yellow background
Alpha Channels (A-Sprites) Alpha Channels
Z-buffers (Z-Sprites) Alpha Channels/Z-Buffers
Tile 1x1x3 Square of the Grid
By Heather Castillo

A lot of controversy has been floating around regarding the use of 3D models for objects and characters. SimFreaks makes no secret that we often purchase 3D models from the 3D community to make objects for "The Sims." However, the terminology from the 3D Community to The Sims Community does not crossover, and this can cause quite a stir of misunderstandings regarding usage.

The Sims is a hybrid game of 3D characters (Sims) in a 2D world of Objects (2D Renders).

Fester Ghoul by Anton
When converting over a 3D head, some of the model does go into the Sim. The meshes we have used in the past were completely destroyed with the conversion process making reverse engineering impossible. We've worked hard to secure permissions for redistribution of these models, that are actually attached to original sim character heads.

Sim objects (2D renders) are completely different. The object models are converted from a 3D Model to Sprite art. Sprite art comes in bmp format as a render at 4 angled views (sometimes mirrored, sometimes not). This enables sims to walk through the 2D world from a fixed perspective, much like an avatar.

How does this work? The game is set up on a grid (1), much like in 3D. The grid assists in many things, such as routing and placement of objects (sprites). Sprites (2D renders) are created from each object (mesh) and may be placed in a fixed position at one of four angles. This creates the illusion of 3D. In image #1, we see a 3D Character, Fester sleeping in a 2D Bed Render. This undoubtably confuses 3D artists. How can we make this happen?

Each image is taken from 3D (or 2D images even) and converted to interactive 2D renders though a series of sprite art. Artwork must be split over tiles to create anything that expands the 1x1x3 box of a tiles space. The studio lamp in image (1, 2a, 2b, 2c) is a render of 3D artwork. The lamp was rendered in an "on state" and "off state" which enables it to light when the 3D character interacts with it.

Image 3a (below) contains the alpha channel which determines the area the object will fill and created the anti-aliasing of the object to make it appear smooth in the game.

Image 3b (below) contains the p-sprite image of the object at front facing render.

Image 3c (below) contains the z-buffer of the lamp, which helps determin the depth of the object within relation to the grid and objects that interact with it. This makes it possible for Fester to put his hand behind the lamp (2c)(left) . Because the z-buffer has given the lamp a depth relative to the space on the grid.

Same is the case of Fester sleeping in the bed (1a). The blanket is part of the bed, but the sprite art allows for an illusion of depth. The blanket z-buffers are darker than the matress and pillow z-buffers, which allows Fester to sleep on top of the pillow and matress, yet under the cozy blanket.

3a - off 3b - off 3c - off
3a - on 3b - on 3c - on
3a - off (back) 3b - off (back) 3c - off (back)

See Objects Overview, Alpha Channel and Z-buffer tutorials for more indepth information.