Halo or Shadow on Grass Sculpt

[AimlessDrifter]

I have been trying to build grass. I have a particular PNG texture I am very fond of, but it has an unappealing shadow (sort of like the halo that is commonly seen on tree prims). I found a bit of dirt on the transparent part of the texture and cleaned that up in Gimp. I have also tried to lighten the top of the blades of grass, with no improvement. In fact it appeared to get worse after after I cleaned up the transparent background!

I am completely confounded, and was hoping maybe someone has experienced this before, or has some suggestions on what to do to get rid of this shadow effect. It's hard to explain, so I have attached a screenshot. The shadow I'm speaking of is on the far side of the grass prim at the top. Thanks in advance for any and all input.

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[Amethyst Jetaime]

I think it is the natural result of how SL light works.  You can test to see if it is the texture itself by turning it to full bright.  If it is the texture you'll still see it, otherwise if you don't it is just the lighting effect on the textured prims.

[Kwakkelde Kwak]

It looks like the normals are the cause of this effect, the direction in which light is reflected.

On the left a section of the situation as is, on the right how to fix it.

 

The red arrows represent the normals at the vertex (the points that make the shape). The blue arrows represent the normals in between, as calculated by the viewer, based on the red arrows.

With sculpties. the red arrow depends on the shape, on the angle between the two adjacent surfaces. It sits exactly in between. So what you need to do is make sure the angles are correct. This can be done by adding some extra vertices near or even at the very top of the shape. The effect still occurs, (the upper blue arrows between the 3 green vertices at the top), but is minimised to the area between the vertices. The closer the vertices are together, the smaller the area that's affected. If the vertices occupy the exact same coordinates, the effect is not visible.

You don't need three vertices btw, two vertices make a prefectly sharp corner, the normal direction depends on the angles of the surfaces and only one surface is present with two vertices in one place.