specular map issue

[ArtemisGreece]

Hello all. I have a problem. I make my mesh statues in blender and I apply specular maps in sl. When I rez my finished statues sometimes I get this https://gyazo.com/4f2fdd9971f37c9d6a869b9eb46186b2. The surface is one face in blender. How can it be looking like two faces in sl?

[Rolig Loon]

You have a second problem.  Your Gyazo image is inaccessible. 

[arton Rotaru]

Yeah right, the gyazo link is broken because of the trailing dot in the link. Removing the dot will reveal the image.

How many triangles does this mesh have? If it's more than 21844 triangles in a single material, the SL importer will split the mesh into multiple materials on it's own. This does happen for collada exports which saves the geometry in <polylists>, rather than in <triangles> lists. Which is what Blenders exporter does, <polylists>.

Your issue could be something else as well though.

[Klytyna]

Unless you are using "edit face" to apply the maps in SL, it shouldn't matter how many faces the mesh has, if you edit a rezzed mesh, and do not use the edit face option, you apply diffuse/normal/specular maps to ALL faces.
 

[Chic Aeon]

That looks like a horrible case of "phong" :D. Any chance your texture has an alpha channel?   I can't remember ever trying to make a texture with an alpha channel have a specular.  And I am off for the day so not going to try now :D. But a possibility.  Does it ONLY look this way with a specular map or does it have the issue before applying?

And to be clear you are saying that you only have one MATERIAL applied to the statue? Only one UV map?

 

[arabellajones]

I've used specular maps with colour and alpha in one image, no problems. The alpha channel doesn't affect the visibility of the diffuse texture, though the items I do this on don't have an alpha channel in the diffuse texture. An alpha channel is a lot of bits to download if you don't need it.

If I just want to get the controls, I use a very small 50% transparent texture. You could use the full transparent texture setting, but it's a bit big. For some things a low specular reflection makes a big difference to the final look.

I've used a version of the diffuse texture, with added alpha channel, to vary the colour and intensity of the material. The Lindens use the word "modulate" which, when I first saw it on their Wiki page, fell into the "everyone already knows" category of unclarity. Some things just don't get explicitly defined. So some components of the garment are shiny, some are not. One obvious feature to use this on would be a belt with a metal buckle.

Edited May 16, 2017 by arabellajones Resident
bad typing

[Rolig Loon]

6 hours ago, arabellajones Resident said:

[ .... ]

I've used a version of the diffuse texture, with added alpha channel, to vary the colour and intensity of the material. The Lindens use the word "modulate" which, when I first saw it on their Wiki page, fell into the "everyone already knows" category of unclarity. Some things just don't get explicitly defined. So some components of the garment are shiny, some are not. One obvious feature to use this on would be a belt with a metal buckle.

So, you make the buckle a separate material from the rest of the belt and then either apply different specularity parameters to it or apply a different spec texture to it, or both.

[arabellajones]

Well, apart from the limit on the number of materials on a mesh object... And multiple materials need edges in the right place.

Also with normal maps as well you can add surface features without using triangles, for instance a chromed rivet. But less blatant, a pair of denim jeans. You don't need polygons to define the seams, the pockets, or the rivets, and the rivets are a bit more reflective than the fabric.

I use the GIMP, and there is an add-on called InsaneBump which can give you a bump map from a height map. I'd use several layers for that, for the seams, the rivets, and some creasing. From the rivet layer I could derive an alpha map for the specularity and normal maps..

Some of the details are here https://wiki.secondlife.com/wiki/Material_Data but a few things are left undefined in an "everybody knows that" state. I had to do a bit of digging to find out that the "specular exponent" and "glossiness" are the same thing, and then they leave "modulates" without a definition.

I think an opaque alpha channel is the maximum value and that becomes no-change, an x 1 multiplier

I have seen a few things that seem to do odd stuff. Where one material is the same specularity, I use a very small 50% transparency texture to activate the dials. And I wouldn't use 100% transparency on anything. That's zero reflection

Most things should have a low level of specular reflection

Anyway, an alpha channel in the normal map locally affects the glossiness of the material, while the alpha channel in the specularity map affects the intensity of the reflection.

I'm lucky that I had done a few things with cgi modelling before I ever needed to look at how Linden Lab does things.