HELP! Custom Vertex Normals are not preserve when delating a face in Blender 2.8. Missing feauter?

Hi Blender Artists, I wish to preserve my custom vertex normals when deleting a triangle face. They are custom and good how they are. But Blender modify them after I delete a face! Blender is averaging of all surfaces normals calculated using the and that is wrong. here is an example:

I know that I’m using doubles to show you better the problem
The problem, is also there when deleting a normal quod.

Is there in Blender a way or option to preserve normals? I wish that blender does not recalculate and make a bad modification of my custom vertex normal. What toggle I’m missing? Is there a boolean to preserve them when deleting a face?


They are an average, however if you see two divergent normals like this at any particular vertex, it means that you need to merge the verticies there, as there are two on top of one another. Your example in the second frame shows that you have 3 points 6 verticies that need to be merged.

1 Like

Thx ajm! but maybe my English is poor or my final image merge was confusing.

My custom vertex normal direction (acronym: “cvnd”) of my mesh are always (by design) pointing to a better direction than Blender average vertex normal direction (acronym: “avnd”). I do not merge, cut or split in Blender because, if I do so, Blender rebuild the vertex direction and making an average[*]. I do not whant that. I want to preserve my cvnd (custom vertex normal direction)! Because are way better than what Blender avnd do.

Is there in Blender a way or option to preserve my cvnd?

FIG(2): Up left screenshot, muy mesh with better cvnd. Upright screenshot, the avnd by Blender after deleting the face. Is not preserving my cvnd. Middle boton there is a photoshop mix of the two to show the change of vertex direction. So in the case of Fig2, vertex are merged. It is just to show the change of direction. In Fig2 I show my cvnd with perfect radius (curvature type of deegree1) so that you can compare with Blender acvd with elipsode (curvature type grater deegree)[looks like a bicorn?].

FIG[1] Was just to show that a lot of Blender function destroy my cvnd . If I merge that particular point, avnd is applied and I’m losing my cvnd.

[*]Average is not good becuse make the average of the vertex that are between the flat zone edge end and the biggining of a constant radius zone. Destroing the radius continuity direction that finish perpendicular to the flat zone and making a more smooth continuity. Creating a nice smoother transition that in Italy we call it (IT:“una spazzolata sul radio”, ES:“sepillado”, "Passing the brush at the end of the radius ") . And that is what in cheep industrial object do not have. They do not have a transition beeteen flat zone and radius, crating almost a line in the reflaction. Since I’m making a cheep Industrial mesh object I whant the in the vertex notrmals that Hard Surface feeling is preserve.

Have you tried using this option here


Usually I have to clear this with imported data from other packages, as they can come with their own normal data and not look good. Here I would think that you can add your own.

More info here