Maya glow transparency problem

RichEnv

Hello everyone,




I'm having some trouble getting the glow underneath this sports car to appear correctly. I need to create a PNG of this car with a glowing effect beneath it. The glow appears fine if there is a plane beneath it. However, once I remove that plane and allow it to glow over empty space (camera environment is black), it becomes severely pixelated and gets dark and muddy along its edges. Anyone have any idea on how to fix this. I tried to remove black matte in photoshop but it doesnt completely fix the problem and it only makes the glow look more pixelated. Any help would be appreciated, Note: this cannot be done in post as the end goal is to create an image sequence of the car and glow animating.

haiddasalami

Something you could do is make a plane for the glow and have an alpha if the camera is fixed like the 3/4 camera view you have it should work

MeintevdS

Render settings (mental ray) > quality > Framebuffer (bottom of the tab) and then uncheck "Premultiply".

This should fix it I think.

RichEnv

Creating an alpha plane with a bright blurred color to emulate a glow is my last choice since it doesnt have the nice glow color bleeding onto the car's body.

Also, turning premultiply off made everything so much worse. It introduce even more artifacts and caused the glow to become a complete mess.

bugo

while doing premultiply instead of using tga, try png.

RichEnv

I have only been using PNG's when rendering.

MeintevdS

Hmm it works for me to get rid of outlines around my renders, but I guess glow is another piece of horror then. Sorry.
Just to be sure, did you save the png and test it in photoshop? Because premultiply will make the render look absolutely awful in renderview since it replaces the black background pixels with whatever color closest to the transparent pixel.

It won't get rid of it completely but might make it less obvious, you can change the background of your render to a more blue color so at least it won't be such an ugly black glow.

Warheart

I second MeintevdS's suggestion. Unchecking premultiply in the MR framebuffer settings should be the way to fix this.

Again reiterating what MeintevdS said:
Without premultiply you'll probably see large blocks of solid colour surrounding the glow when you view it in fcheck but if you save it to a format with alpha e.g. png or psd and then open it in photoshop the colour should fade out correctly without going black.