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Twinmotion refraction IOR?

JohnJay
Expert
Does TM support IOR?

e.g. pool water?
AC27 | i7990x | RTX4070 | W10
7 REPLIES 7
Emre Senoglu
Expert
Nope, TM is not that advanced yet. Refraction is still a difficult aspect to visualize in realtime. If you mean caustics, TM doesn’t support real caustics however it offers a way to ‘fake it’. In fact it looks quite nice in my opinion.
AC26 ARM // MBP M2 Max // Twinmotion | Corona | Rhino

www.senoglu.co

JohnJay
Expert
That's a shame - I do a lot of work with pools so IOR is important to me.

Thanks anyway
AC27 | i7990x | RTX4070 | W10
Emre Senoglu
Expert
i doubt any realtime gpu renderer would be able to give you accurate caustics. corona can calculate good looking (and real) caustics, and im guessing so can vray. i think for being 'fake' caustics, TM actually gives pretty good results. have a look at these two examples.

AC26 ARM // MBP M2 Max // Twinmotion | Corona | Rhino

www.senoglu.co

JohnJay
Expert
It's the IOR (bending of rays) i'm more interested in, though caustics make a big difference too.

Here's a simple (WIP) example - with and without the correct IOR (1.33 in the case of water) most clearly visible looking at the steps in the pool and the overall pool depth.

And one with caustics too. TM caustics are OK but 'real' caustics are more believable.
AC27 | i7990x | RTX4070 | W10
Emre Senoglu
Expert
caustics and real refraction calculations are nowhere close to what gpu's can render realtime for now. even unreal, which i suppose is the most advanced realtime gpu renderer, can't calculate these realtime. so i imagine it will be a long while before you can see actual ior in gpu based (ie realtime) renderers.

quick edit. i think UE has maybe recently added, or is about to add realistic caustics / refraction.
AC26 ARM // MBP M2 Max // Twinmotion | Corona | Rhino

www.senoglu.co

JohnJay
Expert
thanks - i'll keep an eye on UE
AC27 | i7990x | RTX4070 | W10
Carstenem
Expert
you could fake the change in depth in TM like this, not realistic as in real life but hey better than nothing

I did a quick mock up to show you what I mean. In the second image I scaled a copy of the steps by 50% and added a new tiles floor plate which I moved up.
Carsten
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AC 3 to 26 -Windows 7 - 24GB - 8core 4.4Ghz