Title
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A Different Perspective on N-Gons
Category
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Modeling
Abstract
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Quality & topology of a model is determined by how it is modeled.
Introduction
🤔 N-Gons are one of the most debated topics in 3D modeling! They’re usually associated with smoothing artifacts and ‘bad’ topology.
Figure 1. N-gons where cylinders intersect.
Figure 2. Zebra matcap showing smoothing artifacts around the intersection area.
Attempt to Fix N-Gons
😤 When n-gons are present, the initial response is to convert them to quads. It’s common to manually edit and reroute topology to eliminate n-gons. In this case, despite having only quads, shading artifacts are still present.
Figure 3. Eliminating n-gons using rerouting tricks.
Figure 4. Same mesh in Fig 3 showing shading artifacts.
Figure 5. https://topologyguides.com/
⁉️ So how do we have clean shading? First, we should change our perspective. Instead of focusing on eliminating them, we should question why we have n-gons in the first place.
Problem Is the Base Mesh
💡 If we zoom out and see the bigger picture, we can see that underlying shapes don’t have a consistent geometry density. The cylinder is denser than the pipe. Edges don’t align and they have nowhere to go, which produces smoothing artifacts and n-gons. To solve this, we should go back to the block out.
Figure 6. Showing the process of how we got here in the first place.
Figure 7. Base mesh. Highlighted edges have nowhere to flow.
First, ensure that the base shape, the pipe, has sufficient geometry to support different shapes and details.
Then, adjust segments of the cylinder for consistent geometry throughout the model. This consistent geometry will ensure continuous edge flow across different meshes.
Figure 8. Adjusting geometry density to achieve consistency. (Sorry, can’t animate curves in Blender 😭)
💯 After reworking the block out and applying booleans, we now have a solid foundation we can work on. When the base mesh is well-established, the model will subdivide smoothly despite n-gons or other nuances. Also a good base mesh allows us to easily eliminate n-gons if required.
Figure 9. Process of getting a full quad result.
Figure 11. Process of getting an ‘n-gon’ result.
Figure 10. Full quad high-poly.
Figure 12. A different variation with n-gons.
Conclusion
🦉N-gons, vertex poles and booleans are often blamed for causing problems. Try to zoom out and see the bigger picture. The problems we face when modeling are usually foundational problems that resurface during the latter stages of the workflow.
🌊 Having a good understanding of fundamentals and taking time to make a proper block out is the best way to avoid n-gons. A proper block out and base mesh will give a proper result; and not because n-gons are eliminated, but because we made a proper block out! Topology is a byproduct of how something is modeled. Hence ‘learning’ topology and focusing too much on topology is misleading.
🌳 Focus on the foundation, nuances are unimportant.
Figure 13. Reflective matcap on the ‘n-gon’ result.
Figure 14. Reflective matcap on the full quad result.
Pass the word. 🗣️
Teacher’s Archives — December 2024