Modelling & Texturing Guidelines

All art assets should be constructed and textured adhering as closely to the reference and concept as possible. Geometry should be built economically, with a polygon and texture resolution to fit their game play requirements whilst ensuring they convey a faithful reproduction of the real world settings.

Pipeline

Below is the pipeline that every asset will go through. You must follow this when working on the asset you have been set. If you do not show the relevant people your work at each stage there’s a very high chance you will get to the end and be told to do it again.

Modelling Guidelines

Below is a list of guidelines and standards to adhere to when creating scenic assets.

Basic Guidelines

• The assets should be created in max 9.
• The asset should be aligned so that the front is visible in the Front viewport.
• The asset, materials and maps should adhere to the specified naming convention.
• Ensure verts are welded.

  

• The intersection of separate model pieces is allowed; a judgment call must be made on when the use of intersection saves polygon count over mesh consistency/stability.
• Ensure all face normals should face outwards (or as seen) be aware of flipped faces.
• The asset Origin should be at 0.0.0. Reset the transform and collapse before exporting.

Naming conventions and file structure

• The filenames should be in the following formats:

  max: object_type_00.max
  

  psd: object_type_00.psd
  tga: object_type_00_d.tga
  export: object_type_00.x

  The number represents a variation of the asset. Do not include back

  ups of the completed assets. In the situation where multiple max files would share the same texture files then that texture file should have both number variations in.

  The tga files need a postfix that denotes the type of file it is:

  _d = diffuse
  

  _s = specular

  _n = normal
  _h = height

  _a = ambient occlusion

  examples: light_small_01.max

  chair_blue_02_d.tga

• The filenames should have no more than 20 characters plus the file extension.
• When all the parts of the assets are completed they should be put in a folder with the asset name. This folder can then be zipped and sent to the 3d lead.

  

Example folder

Additional

• Model in a representational amount of detail, but do not over complicate, detail can be textured in.
• Afford most of your polygon assets to th ose within the playable area, anything beyond this area will need less detail.

• Pay careful attention to your smoothing groups, these are important as they define the shape of the model.

• Avoid non co-planar and non co-linear polygons (bent quads or polygons with 3 verts in a line), as they do not convert to game well.
• It may not always be beneficial to weld certain pa rts of the object together, for example all the stairs on a staircase.

Bevelled edges

Assets should have bevelled edges applied as this substantially improved the quality of the model in the way that it will interact with light.

Bevelled edges on an object

Poly Count

There is some flexibility within the polygon count for a

ssets. With the unreal engine we will be using more polygons than we have been able to use before but the general rule of thumb is Don’t use polys where they aren’t needed. The lower poly the model is the faster the game will run.

A: Object built using a reasonable numbe

r of polygons
B: Excessive use

of polygons does not improve object

Units and Scale

All assets are to be built to a rea

l world scale. Refer to your project manager for the correct unit setup and reference model.

Stripping

When working in Max the artist should build a model that will strip efficiently when exported into the real time engine. In order to do this, three main areas need to be taken into consideration: Mapping, Smoothing and Structure.

Stripping

· Mapping

Areas that need to be tiled should b

e mapped using the “polygon planar projection tool”. This will ensure that all the vertices are sharing the correct UV coordinates.

Whenever possible avoid mapping a quad and then tiling the geometry to create a surface; this method will result in a mesh that will not strip efficiently.

· Smoothing

Any area of polys where stripping is desired needs to share a smoothing group. A “Hard” edge will stop the surface from being stripped. This is not to say that all edges should be smooth, use hard edges when necessary – on the edges of buildings for example.

· Structure

When creating objects try to avoid producing polygons that fan outwards. Meshes should conform to a grid like struc

ture wherever possible. Fan shapes will not strip. The 3 images below are examples of this; the two to the left are how a mesh should not be modelled, the third image to the right is how a mesh should be mode

lled (note the grid like structure).

Texturing & UV Mapping Guidelines

Below is a list of guidelines and standards we adhere to when creating a scenic building.

Basic Guidelines

· Textures are to be created using Adobe Photoshop

· Textures must be one of these sizes : 2048x2048, 1024x1024, 512x512, 256x256, 128x128 or 64x64

· Textures should be shared where appropriate, ie 2 identical chairs should not have exclusive textures

· A combination real world base textures and Photoshop techniques should be used when creating your textures.

· You may find it preferable to work at a larger resolution when editing the UV’s for clarity of point placement, sizing down at a later date.

· Maximise the use of your texture sheet.

• Textures should be saved in the .tga format.
• Textures should adhere to the given naming conventions.

Unwrapping guidelines

· Fill as much of the box as possible

· Duplicate areas can be overlapped

· Every part of the model should be unwrapped but try not to waste time unwrapping unseen areas to a high detail.

· Make more detailed faces bigger than less detailed faces on the texture page

· Make sure all pieces are facing the correct way, if they are not then when a normal map is applied then it will go inverted on the pieces that are not facing the correct way. A easy way to check is to apply a texture with text on and see if it can be read.

Photoshop guidelines

All the different textures (e.g. diffuse, normal and specular) should all be in one Photoshop file before been saved out as different .tga’s. To keep from the Photoshop file getting messy the layers should be arranged into different folders.

Photoshop files authored for each texture set should contain the following:

Diffuse Map:

Diffuse texture

The diffuse texture should have as much light information removed from it. Windows should have reflections removed and replaced with a texture that represents what the texture would look like without reflections.

Specular Map:

The specular map is black and white and is used to control how shiny/reflective parts of the texture are. Black will be used for parts of the texture that appear matt, and white would be used for something that 100% reflective e.g. a mirror. In most cases the majority of the specular map will be shades of dark grey. If you want the specular to appear reflective rather than just shiny you will need to add an environment map to the shader in max.

The specular can also include colours, a good example of a situation of when to use a coloured specular would be on something like a beetle shell:

Height (displacement) Map:

The height texture can be used to help create the normal map. Areas of the texture are painted to show how high or low they should appear on the model. White is 100% high and black is 100% low. To create the effect of bevels etc the edges of the height map components should be faded using a glow effect.

Height map texture

For the unreal engine any height (displacement) maps created need to be saved in the alpha channel of the normal map texture. Do not use a displacement map on your texture unless asked to because at this stage we are unsure if we will be using them atall

Normal Map:

Normal maps are a way of creating the impression of a bump or indent on the surface of the model. The main thing that needs to be remembered when working with normal maps is that they do not actually move the surface of the polygon to make it stick in or out, all they do is add shadows and highlights in real time so it looks like that is happening.

In order to be good at using normal maps you will need to understand almost everything on this tutorial:

http://www.poopinmymouth.com/tutorial/normal_workflow.htm

The first two pages of that tutorial are not as important for this project because they are about baking out normal maps from a high poly source but the 3^rd page is very useful for what we are trying to do because it explains in detail how to add texture in Photoshop with normal maps.

Exporting to engine

Asset completion checklist

On completion of any asset, the following checks should take place:

• Remove any textures/ materials from the material editor that are not used.
• Ensure the correct material is on the asset.
• Remove any smoothing group problems and ensure bevelled geometry has the right smoothing applied.
• Unhide and delete any unwanted geometry, lights, cameras or helpers in the scene and make sure there are no hidden verts or polys in the asset.
• Ensure that all verts are wielded up if they need to be.
• Select the mesh and make sure the x-form is reset and the normals are facing the correct way.
• Ensure the pivot point is central to the mesh but the z value is set to 0. The whole asset will then need to be set to 0,0,0 in max world space. In the case of small objects that meet the ground, the pivot point should be positioned centrally to the portion of the object that meets the ground.