Lava Shader difference between IPR & Bucket Render

[AC5L4T3R]

Hey hey,

Yesterday I started following this tutorial https://docs.chaosgroup.com/display/...of+Molten+Lava about molten lava albeit with different geometry as seen below. I've noticed that when I'm running IPR mode, it's hit or miss whether I see the cold lava or not. If I go to different points on the timeline, sometimes it'll appear and look really good (as seen below) but when I go to render it, the solid/cold lava just isn't there. I did a quick animation test of every 5 frames for 150 frames but you never once see the solid/cold lava but it does still appear during IPR.

Anyone have any idea what could be causing this? Scene file is here

Please note: The images below were rendered at different frames, however the image on the left was rendered at an earlier frame than the image on the right (very confusing, I know - Seems like an IPR bug).

[georgi.zhekov]

Hello,

Indeed there is an issue when changing the frame during IPR when there is a Grid Texture and Motion Blur in the scene - both the mesh and the grid texture are not updated correctly.
As the IPR support for PhoenixFD is still work in progress I would advise you to stick to production rendering in order to get correct results.

Thanks for the report - I have logged the issue in our system and I hope we'll have a fix soon.

As for not seeing the cold lava - this is due to the way you have set up your viscosity. The difference between the lowest and the highest viscosity is way too small. Increasing the contrast of the noise texture you're using for the Viscosity mask should help, though you will need to sim again and this will change the behavior of the lava.

If you do like how the lava moves now - you can just change the Output texture that is connected as a mask for the Lava blend material and change its Output amount to 3.4 for example and this would add more contrast to your mask and show up some of the cold lava.

Cheers,

[AC5L4T3R]

Thanks Georgi. I'll give it a shot when I get home.

[AC5L4T3R]

Looking better now! I'm having trouble understanding the Parameter Modifer.. How can I get the liquid to stop emitting 30 frames or so before the end of the animation?

[georgi.zhekov]

You can keyframe the outgoing velocity in the Liquid source options. Just keyframe it to 0 and it will stop emitting liquid.

[AC5L4T3R]

Thanks!

This is what I have at the moment..


https://www.youtube.com/watch?v=kfxQVrC8rTA

How can I make it so the liquid starts to completely solidify on the ground working its way up until the skull is encased?

[Svetlin.Nikolov]

First, you will need more liquid in order to fill that volume.

Then you could solidify the liquid by increasing its viscosity using a Particle Tuner. Your tuner condition coild be Age > 1 second for example. Don't forget to export particle viscosity and age from the Output rollout.

Cheers!

[AC5L4T3R]

Thanks Svetlin, I'll give it a go.

When I mean encased (maybe I used the wrong word) but I mean around the 5th or 6th frame the lava solidifies so in this frame it's completely solid.

[Svetlin.Nikolov]

Keep in mind that fluid particles would always try to behave like a fluid, so if you want to freeze them, you can either use a drag force for the entire simulator, or again use a tuner and force the velocities of certain particles to 0. The viscosity would not be able to completely freeze the liquid - it also works more strongly with higher scene scale and with more steps per frame.