Les 2 game 3d - texturing & materials
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Transcript of Les 2 game 3d - texturing & materials
WHAT ARE TEXTURES?
Textures are bitmaps containing color information, which are applied to a 3D object.
• Diffuse map: contains the object’s color information• Alpha map: can be used for transparency control• Specular map: influences the object’s glossiness and reflection (color)• Normal map: can add extra detail without geometry
CREATING TEXTURES
Textures can be made from (existing) photographic material OR be homemade in Photoshop.
PROS & CONS – PHOTOGRAPHIC MATERIAL
PROS:• Fast results• In most cases looks more realistic• More natural look & feel
CONS:• Intellectual property can be a big issue• You have less control over the image• It can be hard to find / take the right picture
PROS & CONS – HOMEMADE MATERIAL
PROS:• Fast results• You are it’s creator, therefore it’s owner• More control over the image
CONS:• Can be slow to produce• Not always the most realistic results
EXAMPLE 1 – HOMEMADE vs. PHOTOGRAPHIC
PHOTOGRAPHIC HOMEMADE
EXAMPLE 2 – HOMEMADE vs. PHOTOGRAPHIC
PHOTOGRAPHIC HOMEMADE
BEST PRACTICE = COMBINING BOTH
Go out, smell the air and take pictures, but keep the following things in mind!
• Camera angle - try and get the right perspective• Lighting - no flash, use a tripod instead and a longer shutter time!)• Patterns & tiles - when going for tileable textures watch for
distinct patterns and spots that might mess up the tileability
TAKING PICTURES – TILEABLE TEXTURES
TILEABLE OR NOT?
TAKING PICTURES – TILEABLE TEXTURES
Nope!
UVW-MAP AND TEXTURES
Textures which are applied on a 3D model with the help of a UVW-map are called unique textures.
UVW-MAP
SHARING TEXTURE SPACEIt’s a common and good practice to use your UV-space as optimal as you can!
SHORT TEXTURING
ASSIGNMENTPick a tutorial from the list (see Facebook for link) and
create your own homemade texture in 15-20 min
Post your final image on FB!
ALPHA CHANNELS
• An RGB bitmap contains 3 channels: Red, Green and Blue.
• Besides these channels that hold color information they can also contain grey scale color information = ALPHA CHANNEL
They can be used for multiple purposes but are often used for transparency and masking
ALPHA CHANNELS - MASKING To mask certain areas of
a texture (especially with leafs) you apply 100% white to areas you want to see (opaque), and 100% black to the areas you want to hide
ALPHA CHANNELS - MASKING In some game engines (like UDK)
it’s best to use a separate 24-bit texture for alpha masking as the engine uses more resources if you add the information into a separate channel of your original texture, making it 32-bits.
ALPHA CHANNELS – GLASS Alpha is great for glass, where
you want to have semi-transparency, still leaving a bit visible for the human eye.
Tip for your car’s windows!
Sometimes materials are confused with textures, which they are not! Materials contain a set of textures and instructions to simulate particular attributes. They often contain what we’ve discussed so far:
• Diffuse map• Alpha map• Specular map• Normal map
LET’S TALK ABOUT MATERIALS..
• Influence the object’s glossiness and reflection
• Most game engines use the color info for reflection, but not all
SPECULAR MAPS
SPECULAR MAPS - EXAMPLE
SPECULAR
DIFFUSE
Most common mistake done
SPECULAR MAPS
Most materials in real life can be classified into 2 different classes:
• Conductors – They conduct electricity, like metals • Dielectrics – They do not conduct electricity, like wood
SPECULAR MAPS - EXPLANATION
Most materials in real life can be classified into 2 different classes:
• Conductors – They conduct electricity, like metals and Light reflected by specularity IS affected by the diffuse color • Dielectrics – They do not conduct electricity, like wood. Light reflected by specularity is NOT affected by the diffuse color
SPECULAR MAPS - EXPLANATION
• Metal (conductor)
• Wood (dielectrics)
SPECULAR MAPS - EXPLANATION
• Specular maps are ADDED (just like the layer option in Photoshop). This is why only saturation will not be helpful in case of a wooden texture!
SPECULAR MAPS - EXPLANATION
Want to know more? http://www.manufato.com/?p=902
• Do not flatten your image and start editing it!
• Add extra detail to the specular map for a nice pop
• Keep your detail layers (scratches, dirt, etc.) separately to avoid frustration later on
• Group and adjust the layers that share the same specularity together
• Try and use the Adjustment Layers in Photoshop. They save a lot of time and can be adjusted on the fly.
SPECULAR MAPS - TIPS
Normal maps are a special category of textures that can add detail to your object without the use of actual geometry.
NORMAL MAPS
Normal maps use the RGB channels in bitmaps to store height information for the detail. This height information is projected on 3D objects and used for lighting calculations.
NORMAL MAPS – HOW DO THEY WORK?
Easiest way to start is with the nVidia filter, using height maps (grey scale height/depth images):http://developer.nvidia.com/nvidia-texture-tools-adobe-photoshop
CREATING NORMAL MAPS
Or nDo, which is fairly similar but easier to adjust things:http://www.quixel.se/
CREATING NORMAL MAPS
Or import your model into ZBrush and add detail there!
CREATING NORMAL MAPS
NORMAL MAPPING - DEMONSTRATION
Tired of looking for good information on the web related to 3D? Try:
wiki.polycount.com
Always up to date, filled with (good) tutorials and in depth explanations of gaming industry’s experts. Check the forums for high quality 3D work as inspiration ;-)
TIP: