3dsmax alpha glitch

PolyHertz

I've been having an issue with alphas in max when making overlapping planes for hair. What happens is the transparency will only work if the planes are overlapping in a particular order (so transparency will work if plane A is overlapping plane B, but not the other way around). This is a problem because I'm using dozens of planes, some of which are either intersecting for a specific effect or the angle they will be viewed at can't be determined. example:



Double sided doesn't seem to want to work either, but thats not as big of concern.

Anyone else had this problem and know of a solution?

Neox

nope thats max, it sorts the objects (not polygons, polygons inside an object is another thing) in order of their first creation, sounds crazy and yes it is o_O

PolyHertz

Bummer . Is their perhaps a way to manually change the order max assigns then?

warby

this is not just a max problem but really every 3d app that supports alpha blending

unless you do alpha testing (i doubt that you can tell max to do that ) which gives you some ugly hard alpha edges but sorts properly or you build you hair with actual opaque geometry ... which will inevitability give you a stylized look in some form .. id say HANDS OF ALPHA BLENDING !

its the biggest anti feature that games have ever gotten it has never worked and will never work ( until we switch to ray tracing maybe i don't know )

edit i just re read my post and its really more a rant about alpha blending rather than constructive help.
so in general if you turn of z buffer writing ( i also doubt that max can do that ) those blank spaces around the tips of your alpha map will be filled with the alpha hair behind it but a whole new batch of graphics artifacts will occur that may or may not remind you of some MC escher paintings where stuff that is further in the back gets draw on top of everything ... personally i like this artifact much better but really both are completely unacceptable.
if you look at how the hair is done in most commercial games lets say dead or alive or soul calibur for example you will notice that only the outer most tips of the hair are actually having alpha blending and you should probably build your hair in a way that the alpha areas will never overlap with other alpha areas look at this picture for example :

http://scr3.golem.de/screenshots/0410/kasumi/kasumi.jpg

no overlapping areas and when do to hair physics and what not it will occur anyway that 2 alpha areas overlap they will only sort wrong rather than masking each other away.



but really just go with all out geometry hair man its "next gen" alright

http://news.filefront.com/wp-content/uploads/2007/06/9608-noscale-heswp30701.jpg

Eric Chadwick

One way that's worked for me is to detach all the hair planes as separate objects. Then re-attach them one by one in the order you want them to sort... first plane will draw first (behind all others), last plane will draw last (on top of all others). This works because the vertices are drawn basically in the order they are created. It only fixes sorting if from your vantage point the planes are still overlapping in the same order you attached them.

Josh_Singh

I do what Eric said. It's just one of those things.

Eric Chadwick

It can actually work, even for fairly complex hairdos. You just have to manually figure out what needs to be in front of what, for a few general arcs of view, like the NSEW points of a compass. Also works for the backfaces, generally those just have to be attached in reverse order.

There are some other methods for solving sorting, but they either require specific hardware (PowerVR chipset, like Dreamcast and iPhone) or non-universal techniques (I'm spacing on the name, but there's an alpha-test variant that's pretty cool).