Triangles Rendering in Cycles?

[FoolishJester]

Hello. Could anyone help please? Whenever I render in Cycles, I get triangles in unwanted places even though most areas are flat surfaces and not irregular or more than four vertices. I’ll attach a render image as well as the edit mode of Evee view.

Thank you kindly!!

[Mateusz]

Hi.
Couple of things I can think of.
Probably not it but worth a shot.

1. Double edges or verts. Sometimes whet you model your stuff it ends up weirdly on the top of each other in edit mode. even merge it all wont help sometimes you need to manually check each edge…
2. Most likely in your case your model is crossing parallel plane on given faces. When modelling in quads i.e. rectangles its important than each of the corner of rectangle is in the same plane. In your case it looks like some vertices are out of their “flat” surface more than they want to be. If you don’t use subsurface modifier blender cant divide that rectangle to more dimensions and is splitting shape in most convenient way cutting it diagonally most efficient way for blender to do so. Cycles is using ray tracing so establishing face position is crucial. as this is its point of reference of where the light rays will end up to be. You wont have that problem in eevee as it is simulating the results so geometry don’t play as much role in this part.
   If you want to keep this look you could try shade smooth than go to “object data properties/normals/ tick auto smooth” and tweak value until you’re happy but its easier to look down the side of the cheek of this guy

[NP5]

As Mateusz has said, your planes are not actually flat. That is common, standard.
All rendering actually renders triangles, they can only ever be flat. All rounded soft shapes involve faking the edge transition.

It goes with the low poly territory. Regarded as a feature rather than an error!

The smoother sculpted look is millions of polys. So millions of very very small triangles. Add on the rendering smoothing faking and near perfect.

[FoolishJester]

Thank you. It’s not the double verts or edges so definitely the “flat” surface. I appreciate the explanation as it definitely wasn’t registering in my head beforehand lol. Thank you very much.

[FoolishJester]

Yes, I agree. Seems to be the logical explanation and good to know for future projects! Thank you very much!