Hair Mesh problem

[JW1]

A while ago I modified a hair mesh slightly (just moving things about, not adding or deleting any verts). The mesh was working fine in the game. Now, I have just installed a new video card and suddenly the mesh is messed up.

 

Here's a picture of the mesh in Nifskope: http://i569.photobucket.com/albums/ss132/JW1a/hairproblem_zps1e123ffd.jpg

 

As you can see, where there are two layers of the mesh the alpha channel of the outer layer is affecting the lower layer too. The original mesh from which I created this one does not have this effect. I've checked and double-checked the various alpha-channel values in my mesh against the original and I can't see any difference.

 

Can anyone shed any light on why this is happening? Why would changing the video card cause this to suddenly occur when it was fine on my old card (old card was an HD5970, new card is an HD7950). Thanks in advance.

[prensa]

JW1 - Hello!

 

Not sure on this but some ideas....

 

Since you've made no change to the hair mesh but have changed your card it seems to point to some setting difference in your graphics driver (I'm guessing you're using Catalyst Control Center with that card).

 

Perhaps a different anti aliasing setting?

 

Also, you may need to let Fallout 3 re-detect your new card to adjust it's settings, is the correct card listed in your launcher or is it the old one?

 

Another idea, you didn't use one of those blanket texture optimisation programs on your fallout 3 files did you?

 

Some of those change textures to lower sized .dds files to save space, which can adversely affect textures that rely on detailed alphas (changing dxt5 or dxt3 to dxt1). Just a thought.

 

Hope this helps!

 

Prensa

[JW1]

Hi prensa, thanks for replying!

 

The game itself is working fine (I did need to get AA and AF running again as the 'detect settings' process turned them both off) and I can put the original hair mesh (the one I based this change on) on my character and there's no problem.

 

I've never used any texture optimization stuff.

 

The problem isn't limited to the game however - the picture I posted was taken from Nifskope.

 

I tried copying just the NiTriShapeData block from my mesh to the original and the effect then appeared in the original mesh, so it seems that the alphaproperty stuff that I had been fiddling with is not to blame. Something in the NiTriShapeData is causing it. I wondered if maybe vertex colours had something to do with it but as far as I can see they are the same as the original.

 

One odd thing I did notice, though, is that my mesh has a smaller number of triangles than the original. Now, as I said, I didn't make any deletions or additions to the mesh, so it seems Blender has for some reason removed or combined triangles. I'm wondering if there was something in the original import or export parameters of my mesh that fouled things up, but then that doesn't really explain why the mesh was fine with the old card. I'm running out of possible explanations!

[prensa]

JW1 - Hello!

 

"One odd thing I did notice, though, is that my mesh has a smaller number of triangles than the original. Now, as I said, I didn't make any deletions or additions to the mesh, so it seems Blender has for some reason removed or combined triangles. I'm wondering if there was something in the original import or export parameters of my mesh that fouled things up"

 

That sounds likely, perhaps some kind of optimisation setting on export?

 

"but then that doesn't really explain why the mesh was fine with the old card"

 

That's what I thought.

 

Could be a subtle difference in how the old card handled the effect, did you update CCC after changing to a new card?

 

I've got next to no experience with hair meshes I'm afraid.

 

I've used NiAlphaProperty a lot though with glass & bottle models.

 

There's a lot of different flag settings that can be used in them, compare the setting in your model with the setting in the working original version & see if it got changed somewhere along the line.

 

Open up in Nifskope & left click on the NiAlphaProperty block, in it's details at the bottom in "Block Details" find "Flags".

 

There'll be a number next to that, it controls the various properties of the transparency.

 

Compare it to the working models settings & change it to make it match if it's deifferent.

 

If no joy there, you could try Spells - Optimize - Split Properties in case it;s sharing some settings it should not.

 

Make sure to make a copy of your model before tweaking in Nifskope. :smile:

 

Hope this helps!

 

Prensa

Edited March 2, 2013 by prensa

[JW1]

I went through my mesh in Nifskope line-by-line checking it against the original and I could not see a single difference (of course, I couldn't check each individual triangle - there are 6000 of them!). None of the Nifskope spells had any effect. In the end I decided to try playing around with the Blender settings. I opened up the original mesh in Blender, made a tiny change and saved it again and voila! it's perfectly all right!

 

I don't understand it, but I don't think I'm going to question it. I've got to re-do the changes I made, but for whatever reason I can edit this new mesh perfectly normally and have it work in the game.

 

Clearly there are some things that Nifskope either doesn't show or doesn't know about. To be honest it's conclusion I've come to before. I've made a lot of simple objects for my mod and very occasionally one will play up and there's no sign in Nifskope that it's any different from any other!

 

It's not very satisfactory to be stuck not knowing what the problem was, but at least I can do what I wanted to do. Thanks very much for your help prensa! :smile:

[prensa]

JW1 - Hello!

 

"I opened up the original mesh in Blender, made a tiny change and saved it again and voila! it's perfectly all right!"

 

Great! Glad you got it sorted, sorry I couldn't be of more help.

"I don't understand it, but I don't think I'm going to question it."

 

Very wise. I'd do the same. :)

 

"It's not very satisfactory to be stuck not knowing what the problem was, but at least I can do what I wanted to do."

 

That's the important thing, you can fix it. :)

"Clearly there are some things that Nifskope either doesn't show or doesn't know about. To be honest it's conclusion I've come to before."

 

I know what you mean, sometimes it's almost like the stars have to be in alignment for a certain model to work. I still love Nifskope though. :)

 

Prensa