Low Poly model - a polygon mesh in 3D computer graphics that has a relatively small number of polygons (judged by the wireframe of an object and it's polygon density). That usually means that the model has to be created for efficient use through good topology. Low poly meshes are used in real-time applications (for example, games) while High Poly meshes are used in animated movies or 3D visualisation. It also depends on the usage of the model - AAA games can handle millions of polygons while mobiles may struggle with 100k. A character with clothes created for AAA games could have ~100k. A character for VR would have up to 70k polys. Simple props usually have up to a few thousand polygons. Whereas huge low poly cities can have a few million polygons. Note that technology is constantly improving so the limits may change over time.
Some tips when creating Low Poly/Game-ready models:
- if the character has hair, it should be made as a polygonal mesh (e.g. hair cards) instead of hair (particle) system. Of course, there might be exceptions (e.g. Unreal strand-based hair in .abc format)
- best if the textures are pbr and does not exceed 4k when not needed
- single sided planes should have thickness since some engines do not have native support for two sided shaders.
Rigged - model is considered to be rigged if:
- Skeleton bones and joints must follow a logical hierarchy (FK/IK). Hard-surface model rigs must have logical parenting of objects, correct pivots/control nulls.
- Correct skinning, weights must be set up (simple model deformations must work as expected)
- Morphs (blend shapes) should be set up correctly
- It is recommended to provide controllers and correctly set up the constraints
- It is recommended to include a bind-pose frame
- Transforms should be frozen/reset
PBR (Physically based rendering) is based on real world values, making it more accurate and consistent under all lighting conditions. It is the technology that powers AAA video games and high end renderers.
Usually two main workflows are followed when creating a PBR model - Specular/Glossiness and Metallic/Roughness. For the model to be approved as PBR in our Marketplace, all core spec/gloss or metal/rough workflow textures must be included.
UV mapping - it is the 3D modeling process of projecting a 2D image to a 3D model's surface for texture mapping. If basic UV mapping is used on your model you can simply select the UV mapping option and leave the Unwrapped UVs option with a “no”. If a more complex mapping was used, you must specify it. You can select overlapping, non-overlapping or mixed. Mixed here meaning that model can have basic UVs together with unwrapped UVs or no UVs at all.
Animated - model is considered to be animated if:
- Keyframes/animation curves are present
- No glitches, hitches, sudden spikes during playback
- Animation designated as looping has smooth transition