Fireflies Problems (SOLVED)

FenixPhoenix

Hello,

I'm pretty new to Daz, been working with it for only a couple of months now and I'm still experimenting with lights. I apologize if this is a question that has been asked before, but I was unable to find a clear answer. My question: how would I go about getting rid of "fireflies" in a nigh scene iray render.

I'm attaching all the screenshots I think pertinent, in hopes that there's a fix within my parameters or settings. Bear in mind, I know nothing (Jon Snow...) and most of the settings I used are mostly by trial and erros. I'm attaching the following:

The render in questio: a nightview from inside the car. Near the sidewalk, you can see the tiny fireflies marring the scene. I'm also attaching my render settings (the things I altered). I've got two distant lights (attachment 6) one purple and one blue somwhere in the scene to create that night feel (each looking in a different direction, up in the sky and looking down). Both lights have the same settings, so I'm only inlcuding one screenshot of that. I'm also using an HDRI night sky map.

Finally, near the car in question (and therefore the fireflies) I have a post light with a "spot light" looking down. I'm including some screenshots to show where it's at as well as the settings.

Any advice on this would be much appreciated!

 

 

mjc1016

Those are not fireflies...

It is more of a 'sampling' problem...there is not enough light/samples to render with default 'stop' conditions.

Position of the distant lights doesn't matter, only direction.

What kind of lights are the headlights and what are the settings for them?

FenixPhoenix

Hi mjc,

There aren't any other lights apart from the ones I stated. The car isn't lighted (headlights would be truned off, if you will). I'm attaching the images showing neither car parked nearby has the lights on. I'm not really sure where that streak of light is coming from. Could it be that the light from the spotlight above bounces off the car? I'll try to do another render moving the car back and see what happens.

Update: Moving the car and adding a Filllight didn't work. They actually form the more time I leave the scene rendering.

Rendering the scene in 3Delight doesn't show the fireflies or white pixels, though.

Tobor

I'm guessing you're not liking the rough reflection on the road? That's caused by the material you've used, and the specularity and reflectiveness set for it. 

You've compared the render with 3Delight, so I'm not sure if the followup captures indicate the surfaces you're using for Iray, but take note you're showing 3DL shaders here. These are "auto-converted" to Iray, but the conversion gives you absolutely no control over how the material looks. If you want to render with Iray, you need to manually convert all surfaces with an Iray-compatible shader, and make whatever changes you need to get the look you want. You could make your road appear like wet cement, or clear glass, or dry asphalt, or whatever.

FenixPhoenix

Tobor,

Thank you, that ended up being actually the case! I tried using the Iray Uber Base to see if that would fix things (attachment 1) but it didn't. So I went ahead and changed the texture of the sidewalk to an iray texture and left the concrete as is to compare (attachment 2). The sidewalk looks ok and the concrete still has those dots. Since I don't want to lose the textures (I'm using Stonemason's Urban Sprawl), I'll just render this with 3Delight. Thank you very much for the input :).
 

Tobor

The dots are specular highlights, which can generate fireflies. But the general appearance of the highlights looks "natural" given the light in the scene, and the type of surfaces we expect here. You can certainly try to tone down any glossiness and reflectivity, and change any glossy/top coat layers so they have a non-white color. They can simply be a somewhat lighter tone of the base. That would work for a night scene.

There are some asphalt and concrete shaders that come with Iray, but you need to look in the nVidia Examples folder. They're separate from the Iray Uber shaders, and they use a completely different approach.

There's also some shader assortment packs you might find useful, especially MEC4D's Shader Pack 2.

If using Iray Uber shaders, remember that you can keep the underlying texture and change just the base shader by holding down the Ctrl key while you apply the shader. You're asked if you want to Replace or Ignore replacement of the textures. Ignore, and then do any cleanup needed. Many of these kinds of shaders will change things like the tiling, which you then have to return to the original setting, or else the textures will look wrong.

FenixPhoenix

Oh, I didn't know that! I have MEC4D's Shader Pack 2, so this should work nicely! I'll try to follow your instructions and see if I can diminish the effect. I'll try lowering the gloss and reflectivity first. Thank you very much for your advice, @Tobor!