gradual transparency method

Started by Dune, June 18, 2018, 08:39:15 AM

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Dune

Got the culprit; doublesidedness of the card (and subdiv settings were needed to get the haze of low res background off).

Hannes


Dune

Yes, but I'm still having problems. There seems to be some inconsistency when rendering; one time background is transparent, but ground turns black, second time it turns white. I had it working once, but in a second render it was wrong again. Very weird. And also when using 2 cards (fire and smoke), it's not always going well.
Okay, painting in is easier, but I'd still like to know why. And it may be something that needs debugging.
So here's a few files (you have to recall png's) and a test I did.
Anyone has a better solution, please post.

Hannes

Weird! If you use two cards there may be some difficulties when there are two glass shaders involved. I had the problem that when I have two objects with glass shaders behind each other the one behind renders black in some cases.

luvsmuzik

You may also be able to do your transluparency trick w/o the glass shader. Give it lots of specular and some reddish/orange luminosity and transparency. I am glad to know I am not the only one this inconsistency happens to, however. Sometimes I even have to change an image made with an alpha channel to alpha from color, fiddling with tolerance also. There has to be some other trickery that gets in the way.

WAS

#20
While this is more of a possible bug solving issue with setup, I still adivse to just do it in TG. You'll have a more natural final product for the scene. Additionally you have animation control and can vary it's look easily for different shots without a repeating stock elements.

I'm not sure if the flames are placeholders or not but they're a lot less realistic than you can achieve with TG alone (little swirly). And of course, my AA quality is limited to begin with, on top of a slow PC, but even with cloud quality adjustments and GI to Still / Very High, it looks pretty darn good

You can get all sorts of looks playing with your redirector and coverage adjust such as negative values for more wispiness, making it much more like what you have.

Dune

I've been thinking to project the flames and clouds onto a small cloud, but still have to test whether that works without too much grain. Is that what you're talking about too?
This is mainly about the principle of the transparency though.

WAS

#22
That is all 100% cloud. Grain is tied to quality which can be rendered out. Like I said my AA is locked in at 6 and grain is minimal with adjustments.

I am not sure how a projection would work though I imagine with similar quality settings to get rid of noise it could work.

Here's a copy with ridiculous cloud quality, still could be better with AA

Dune

This looks very good. So, it's procedural and on real world scale?? I need a campfire of only 50cm across and 1m high or so.

WAS

Quote from: Dune on June 22, 2018, 01:42:03 PM
This looks very good. So, it's procedural and on real world scale?? I need a campfire of only 50cm across and 1m high or so.

I'm sure it could be scaled down, this I believe is based on 2m circle shape masking the base PF. I'll send a clip.

Matt

Ulco,

With your example files I made the following changes:

Enabled both cards.
Enabled 'double-sided surface' on both Glass Shaders.
Slightly moved the position of one of the cards so that they are not in exactly the same place.

The only thing that isn't quite right is that GISD isn't applied to the ground where it is seen through the cards.

Matt
Just because milk is white doesn't mean that clouds are made of milk.

WAS

Here is a fire at 50cm. 12m render time, but the internal cloud quality settings are very high to compensate for my lack of AA. I am sure with a non-free version the clouds would be much easier to denoise with AA over absurd internal settings. Sent you a file.

Dune

Thanks guys. I wonder why I didn't get a good result then, if it worked for you. The cards weren't exactly in the same place when I tried first, but I remember having copied the one working for the other one, and not relocating again for this testfile. I'll have another go.

WAS

Quote from: Dune on June 23, 2018, 01:50:42 AM
Thanks guys. I wonder why I didn't get a good result then, if it worked for you. The cards weren't exactly in the same place when I tried first, but I remember having copied the one working for the other one, and not relocating again for this testfile. I'll have another go.
I've had some wonky stuff happen copying stuff. Who knows.

luvsmuzik

WASasquatch your examples are great! I think Ulco shared a cloud column file long ago that would convert nicely to flames or smoke with little tweaks. It uses a SSS too.
Thanks for the input on those card objects, all. I have used the shattered rock with glass shader for flames also, making the rock more egg shaped (double y value to x&z) That can add some embers in you fire bed. Pops of small fake stones floating around are doable too.