[Help] Alpha Planes....Why do you do this to me ?

AshuraDX

I ran into a problem with some alpha mapped planes while working at my Han Solo Blaster model :
The planes render fine in 3ds max 2015 (default viewport settings, except max texture size)
while the same planes render...well not as they should in the classic DDO's modelviewer and Substance Designer



I really have no clue why the planes render fine from the bottom in every program while the top doesn't is there anything I can do to fix this ?

Chimp

The pic isn't too clear but you say that they render fine from one side and not the other - this is because planes are one sided - you either need to use a double sided shader or have additional geometry pointing the opposite way (up) next to the ones pointing down.

gsokol

What Chimp said.

To see how this looks in max, right click the object, go to properties, and turn on backface culling. Then you will only see the front of the face, and the backside wont render, which is consistent with what any game engine/real time renderer will do.

Chimp

Having had a better look at the picture, I'm not entirely sure why you're taking this approach for this geometry - the amount of overdraw is going to be insane and cause some performance headaches. Cut around the actual visible area or go with some proper geometry

AshuraDX

@Chimp These planes are 2 sided so I actually did what you suggested first allready
this mesh is going to be used in the by now ancient game Jedi Academy, and I am allready quite high in tri and vertex count (even for a viewmodel, which this is going to be) which is why I chose to alpha map the ribs of the front grill instead of modeling them as giving them a round, smooth, appereance would bum up my tri count even further - but I may have to change that now

I'M not sure wether you see the problem here :
the transparent pieces from the up facing planes block out the planes beneath them WHILE the down facing planes don't do that

it must be something with the draw order I guess

EDIT :
"Inverting" the face indices for the top facing planes did the trick (1-18 from bottom to top instead of top to bottom)

Shadownami92

How close will this model be to the camera? considering the ribs are on the front of the gun and likely be less visible from a first person perspective and too far away to see anyways from a third person perspective, is there a reason to just not have the rib painted into the texture and/or maybe just bump it out a little with some geometry?

AshuraDX

it's going to be quite visible, I'm afraid but only from a relatrively low near horizontal angle but I got that alpha issue sorted out here's the model as it looks now, still have to add some scratches to this rough DDO base
[sketchfab]c76bba4c77f5415cbb2f52cf7a894fcb[/sketchfab]
Han Solo's DL-44 Heavy Blaster Pistol by ashuradx on Sketchfab

Chimp

lovely model but those planes look horrific, honestly just do it with some real geometry - the additional polygons are less of a performance drain than 18 transparent pixels on top of each other and look much nicer.

As shadownami92 says, this isn't even player facing and from another player's perspective it's going to be too small to see. real geometry recommended.

AshuraDX

Chimp wrote: »

lovely model but those planes look horrific, honestly just do it with some real geometry - the additional polygons are less of a performance drain than 18 transparent pixels on top of each other and look much nicer.

As shadownami92 says, this isn't even player facing and from another player's perspective it's going to be too small to see. real geometry recommended.

I'll consider it , I guess I'll just cut the shape out of my planes, and do a quick extrude to not mess up my UV's

throttlekitty

I get all kinds of trippy effects rotating the camera around those planes.