Mesh Showing Black Lines in Texture Work

[Sae Luan]

Hello everyone.  First, I understand what generally causes this issue.  I always bake my textures 5 pixels outside the UV lines to try to make sure it doesn't happen.  Today, though, when I logged on and uploaded a new mesh, I noticed there was black lines through all my texture work on the mesh where the UVs meet up.

Thinking I had bumped my settings in Maya back down to where it didn't bake over the UV edges, I went and checked the settings, and sure enough, the textures are baking over the edges by 5 pixels still.

Switching back over into SL to continue trying to figure out what was going on, I noticed an older mesh of mine was doing the same thing, and this mesh for sure didn't do it before to me or anyone else (I have countless photos from bloggers as well as my own snapshots and ad for referencing back).

I relogged like 3 times, then suddenly I was no longer seeing the lines.  I decided to be sure and sent the meshes off to 4 different people, all said they see the lines, and two of the people relogged and were still seeing the lines.  After countless relogs, though, I cannot duplicate the lines.  It happened for about an hour for me, but is now gone, yet everyone else is still seeing them.

So I'm curious.. did anyone else experience this today with any of their meshes?  Also, what is the standard pixel area to extend your textures outside of the UV borders?  I always thought it was around a 3, so I thought doing mine at a 5 I would be safe from having this issue.

If I'm simply not baking or extending the textures far enough past the UV borders, why would it be some people are seeing my items wrong and others are not?  o.O

 

Anyway, here is what they see and what I saw at first - 

and here is what I see now and no one else can see-

[Chosen Few]

Asset server delivery hiccup, maybe?  As you probably know, every texture in SL contains 4 progressive LOD's.  If the highest level isn't trickling in, it could conceivably cause this issue, assuming the peripheral areas are more intrusive in those versiaons.

If that's the case, then a larger bleed could help hide the problem.  You can either set it a lot higher in Maya, or you could bake with alpha enabled, and then use a solidify filter in Photoshop, for 100% bleed coverage.

To clear up the view on the existing textures, I'd suggest you tell thsoe people to clear cache before relog, if you haven't already.

[Sae Luan]

Thanks for the info.  I tend to do my UVs fairly close together, so I'm having to redo the UV layout a tad on part of my newer mesh to allow for a higher bleed during baking.  

I assumed the issue today wasn't due to my own error as I've used these settings countless times in the past and not had this issue (or a complaint for that matter), but it did make me realize that someone else could be seeing the texture incorrectly from time to time, so I've opted to start making sure the bleed is much higher, possibly pairing that up with a solidify in PS as you suggested.

[Chic Aeon]

Just wanted to affirm that I have seen LOTS of issues this last week that seemed very strange. Some temporary, some not. Some on Aditi; some on Agni.So it is certainly possible that it isn't YOU at all. The uploader seems to be having a nervous breakdown . Not helpful to us using it, but try not to go along with the trend.

I have no answers of course, just letting you know you are not alone with "ISSUES!".

[Kwakkelde Kwak]

In addition to Chosen's answer, you can minimise the bleeding by remapping your object. The black lines show in places where I'd never expect them. You want the edges in the least visible places, not across a button, but on the back. Pushing your UV edges to the very edge of the texture can also help in some cases. Your bracelet for example could be unwrapped in a perfect square covering an entire texture. Then even if you get a lot of bleeding, it won't be visible at all. You can do this in one or two directions btw. Whether it's possible of course depends on how many objects/faces/islands you put on a single texture.

[Sae Luan]

Hello.  Thanks for the response.  These are things I know and have done in the past.  It is even something I stress on when someone comes to me for help with Maya in general.  Both of these items were automatically mapped, then adjust using the layout options once in the UV map to save time on my end due to a lot of RL being busy and SL event deadlines.  This is something that did occur to me, however with a decent enough bleed, I didn't feel I should have to go back and redo my UVs by hand when I already am short on time.

It's a good point though, and one that should be noted for anyone else having issues.

[Chosen Few]

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Sae Luan wrote:

Both of these items were automatically mapped, then adjust using the layout options once in the UV map to save time on my end due to a lot of RL being busy and SL event deadlines.

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Just so you know, because Maya's automatic mapping tends to create a ton of indivudual shells (islands), you end up with much higher download costs in SL than you otherwise would.  Each UV point counts as a vertex.  Say three shells have a UV point in common, you've now got three times as many extra vertices as you would have if those three shells were merged into one.  Multiply that by the sheer number of shells the automatic mapping tends to create, and it can really add up fast.  Your land impact can go through the roof on a model that would otherwise be really low.

When I use automatic mapping, I consider it just a starting point.  The very next thing I do is go in with the "Move and Sew UV Edges" tool, to very quickly combine as many shells together as I reasonably can.  On a typical model, you can cut the number of shells down by at least 80%, in just a minute or two.

That said, I rarely take that approach anymore, because a few years ago, I discovered the magic of Unwrella.  It's an icredible time-saving plug-in for UV mapping that works far more intelligently, a whole lot more easily, and way faster than Maya's built-in automatic mapping.

Just define where you want your seams to be, and Unwrella does the rest.  It automatically calculates the optimal UV layout, to ensure uniform texel density, across the entire surface, with the least possbible texture stretching. To do the same thing by hand can take anywhere from 10 to 100 times as long, and the results are rarely as uniform.

Give the free trial a whirl.  You'll be amazed.

When you do decide to buy it, which I'm sure you will, you'll be pleased to find that Unwrella isn't even pricy, at just under $200. With the amount of time it saves, it pays for itself in the first job.

[Sae Luan]

Thank you.  When I have the time to really put into my UVs I also do the move and sew with the edges of the UV borders.  It tends to take me quite a while though on some models.  With most mesh, I tend to use planar projections on any areas it makes sense to do so on then use automatic on areas that are harder for me to nab with the planar method, then go back in with moving and sewing.  Sometimes this goes quick, and sometimes, not so much.  I wish it were quicker for me.

These items are very much a result of simply not having enough time to devote to that part of the release before event deadlines.  

I had NO idea that it adds to a higher download cost to have the extra islands.  That's very good information to have on hand, and I'm going to keep that in mind when constrained for time in the future.  Perhaps I can work in at least a bit of going through and minimizing with sewing.

I learned to UV map through digital tutors.  The course I watched that was specifically over UV mapping was very thorough and informative, however, as I watch courses over other things, I see sometimes the instructor will simply apply an automatic mapping on things and not bother with moving and sewing.  The most recent I noticed this on was a course called "Creative Development: Baking Light Maps for Game Environments in Maya and mental ray with A. Gabriel Betancourt."  It often makes me wonder why some courses don't bother with sewing the UVs into something more understandable and usable.  Perhaps it's not as important to the specific project or maybe automatic mapping is just used to cut down the time on these courses that are not specifically teaching UV mapping.

Unwrella sounds very nice, and I'm going to go check that out as soon as I can get back to my work computer again.  When I first started learning about UV mapping i often thought to myself something like that would be so much easier to work with.  That price sounds very reasonable as well.  Thanks so much for letting me know about Unwrella.

[Drongle McMahon]

While we are on the subject, a little more about the extra download costs that might be useful. It happens because each "vertex" in the upload format has position, normal and uv coordinates, and it appears in a separate list for any material touching it. So a single geometric point has to be a new vertex every time it occurs with a different normal or different UV coordinate or different material. The number of vertex list entries is the major determinant of download weight.

Different normals happen when the vertex is on a sharp edge, so that the triangles on either side have different angle along the edge where the vertex is. Different UV coordinates happen wherever a UV seam cuases the vertex to correspond to multiple places on the UV map, that is when the triangles involved don't share edges in the UV map. Duplication in material vertex lists happen where vertices lie on the border between two materials.

Because of all that, if a vertex has been duplicated for one of these reasons, it may not need to be duplicated again when another applies. In the extreme case, a completely flat-shaded (faceted) mesh (without multi-triangle flat areas) already has the maximum amount of duplication. In that case, fragmenting the UV map will not add more to the download weight. Conversely, smooth shading will decrease download weight only if the UV map is well joined-up. Otherwise the vertex duplication is still there because of the UV fragmentation.

The more generally useful consequence is that UV seams along sharp-shaded edges (between smoothing groups in Maya, I guess?), or along the edges of areas with separate materials, do not add to the download weight because the relevant vertex duplication has already happened. So, and this is the point of all the preceding explanation, placing UV seams along edges that are either sharp or divide materials, when possible, can make a useful contribution to the optimisation of download weights.

[Sae Luan]

Thanks for helping me understand this more!  I had no idea.

[Porky Gorky]

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Sae Luan wrote:

I always bake my textures 5 pixels outside the UV lines......

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It's never occured to me to bake my textures further away from the UV lines. I am really not happy with my texture baking at the moment and I am having to clear up allot of scuffy edges. 

Does anyone know how to change the settings in 3DS Max to bake further away from the UV seams? Thanks

[arton Rotaru]

It's called Padding, and you'll find it in the Render To Texture dialog. Also, don't save out the image from the rendered frame window. It won't have the padding applied.

[Porky Gorky]

Brilliant, thanks allot. :matte-motes-big-grin: