Custom Content Basics - Hybrid 3D

Overview

Over the years SimFreaks has utilized many resource to bring content to the community. The studios we have created works from have been so gracious. At one point, we had some controversy over the usage of 3D from other sites, though after much time, we grew as artists and didn't always utlize 3D Community Art.

Fester Ghoul by Anton
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Mesh & Skin

When this site was originally built, there seems to be a little confusion for some people about the difference between a mesh and a skin. Now that 3D is more in the mainstream of technology, it almost seems unnecessay to explain, but I will anyway, just in case!

A mesh is similar to a wire frame and a skin is the outer texture that wraps around it. Think of it like papier-maché. You make a frame out of balloons or wire, then wrap your paper and materials around it for texture. Maps (that you don't see) determine the way the skin goes around the mesh.

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. If you aren't using your own 3D models, be sure to obtain permission before use.

1a
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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 four angled views (sometimes mirrored, sometimes not). This enables sims to walk through the 2D world from a fixed perspective. The reason the game was created this way was that computers were much slower then, and 3D caused a huge problem with processor speed.

2a
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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?

2b
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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.

2c
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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.

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

Sprite Examples

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