00:00 Hey everybody, Martin from Quad Spinner
00:02 

00:02 here and today we're going to be
00:03 

00:03 discussing the thermal node. Thermal 2
00:05 

00:05 is a node that controls purely thermal
00:08 

00:08 erosion. Now thermal erosion is
00:10 

00:10 something that happens when there is
00:12 

00:12 differences in temperatures in a
00:13 

00:13 climate. So you can think of daytime and
00:15 

00:15 nighttime temperature shifting or even
00:17 

00:17 seasonal temperatures. It is something
00:19 

00:19 that breaks apart terrain by the rock
00:22 

00:22 expanding in the heat and shrinking in
00:24 

00:24 the cold. It can also be exacerbated by
00:26 

00:26 water getting into the cracks and then
00:28 

00:28 expanding as it freezes which then makes
00:30 

00:30 the rock break apart even faster. This
00:32 

00:32 kind of erosion is often seen in
00:35 

00:35 mountain ranges like the Alps or the
00:37 

00:37 Rocky Mountains and it causes a lot of
00:39 

00:39 cliff formation, a lot of talis flows
00:42 

00:42 and it will kind of break your mountain
00:43 

00:43 down from every side. And we're just
00:46 

00:46 going to cover all the settings and then
00:47 

00:47 and further on I will give you some
00:48 

00:48 examples of use cases. So, we're just
00:50 

00:50 going to add a base thermal 2 node here.
00:53 

00:53 And this is our bedrock, our base
00:55 

00:55 terrain. We're going to add this thermal
00:58 

00:58 2 right here. And let's talk about
01:00 

01:00 sliders. Duration is of course the
01:02 

01:02 duration of the simulation. If we
01:04 

01:04 increase this, the effects of the
01:06 

01:06 simulation will be enhanced. Strength,
01:08 

01:08 very simple. It is the strength of the
01:10 

01:10 actual erosion. So, if we turn this up,
01:12 

01:12 we'll just see more strong effects from
01:15 

01:15 the erosion happening without a longer
01:17 

01:17 build time. Anisotropy is very
01:19 

01:19 interesting. It is basically controlling
01:21 

01:21 the level of irregularity of the thermal
01:23 

01:23 stress that your mountain is receiving.
01:25 

01:25 So when your mountain is receiving a
01:28 

01:28 very regular thermal stress, it will
01:30 

01:30 maintain a lot of the details that the
01:31 

01:31 terrain has. However, when the stress is
01:34 

01:34 more irregular, it focuses more on
01:36 

01:36 locations of interest like rocky
01:38 

01:38 outcrops and that kind of stuff which
01:40 

01:40 causes them to be eroded more as there's
01:42 

01:42 more thermal stress happening in that
01:44 

01:44 area. basically eroding your terrain
01:46 

01:46 until there's not much interesting shape
01:48 

01:48 left and it's actually very equalized.
01:50 

01:50 The best way to showcase this is when I
01:52 

01:52 remove all the sediment. So, let me just
01:54 

01:54 turn that up to one and let's turn off
01:56 

01:56 the anastropy.
01:59 

01:59 As you can see, major details like
02:01 

02:01 cliffs and stuff as we see in the base
02:03 

02:03 shape here will still be preserved. Uh
02:06 

02:06 the mountain is still somewhat the shape
02:08 

02:08 that you uh kind of recognize from the
02:10 

02:10 underlying node. If we turn it all the
02:13 

02:13 way up, this is what we get. The
02:15 

02:15 mountain has been absolutely eroded.
02:17 

02:17 It's just completely chipped off every
02:20 

02:20 angle. And uh what we get is a very
02:23 

02:23 smooth, sharp, interesting shape. Uh you
02:26 

02:26 would probably keep the anastropy
02:27 

02:27 slightly lower so you maintain your
02:29 

02:29 shape. Um and then we can actually play
02:31 

02:31 around with some talis.
02:34 

02:34 Now the talis is not directly connected
02:36 

02:36 to the simulation like erosion 2. It is
02:39 

02:39 actually more of an added sediment on
02:41 

02:41 top to just have artistic control over
02:43 

02:43 these flows. But down below, I will show
02:46 

02:46 you a combination of thermal tube
02:47 

02:47 together with erosion to get very
02:50 

02:50 realistic talis flows. So the talis we
02:52 

02:52 get from the thermal tune node is
02:53 

02:53 actually pretty cool because we can
02:55 

02:55 easily art direct the uh slope angle and
02:57 

02:57 stuff of this talis. So if I turn this
02:59 

02:59 down, it will lay down very flatly on
03:02 

03:02 the terrain turning it very rounded as
03:05 

03:05 it's just piling up and kind of rolling
03:06 

03:06 off. If I turn it a bit higher, it will
03:09 

03:09 be a bit more sharp as it's more angled.
03:11 

03:11 As you can see, the best way to control
03:14 

03:14 this is by removing a little bit of it,
03:16 

03:16 especially if you are really using a
03:18 

03:18 higher duration and higher strength of
03:20 

03:20 the erosion. Um, because at that point,
03:22 

03:22 you're starting to build up a lot of
03:23 

03:23 talis flow, which might cover a lot of
03:26 

03:26 cool details. So, if we remove a bit
03:29 

03:29 more,
03:31 

03:31 we can turn up the angle to something
03:33 

03:33 like 60. And now you're getting these
03:36 

03:36 really cool talis flows. And you'll see
03:38 

03:38 some cliff detail appearing. We want to
03:41 

03:41 save a bit more of that. Let's turn the
03:43 

03:43 anastropy down. And then we arrive at
03:45 

03:45 the last setting right here, which is
03:46 

03:46 the feature scale. So the simulation is
03:49 

03:49 looking at your mountain. And at a
03:50 

03:50 feature scale of 25, all the features
03:52 

03:52 that are smaller than 25 will kind of be
03:56 

03:56 washed away by the erosion. However, if
03:58 

03:58 we turn it down, we preserve a lot more
03:60 

03:60 of the base shape because a lot more of
04:02 

04:02 the smaller details are kind of are kind
04:04 

04:04 of inhibiting the simulation from
04:06 

04:06 happening there. But I think a sweet
04:08 

04:08 spot is often like something like 10,
04:11 

04:11 uh, which would preserve quite a bit of
04:12 

04:12 detail as you can see in the cliffs, um,
04:14 

04:14 but still give you cool talis flows
04:16 

04:16 coming down. If you watch the snowy
04:18 

04:18 peaks tutorial, you'll see that I
04:19 

04:19 actually used this kind of technique to
04:22 

04:22 create cool, very sharp uh high altitude
04:25 

04:25 snow, which you know is something that
04:27 

04:27 thermal 2 does really well. So, now that
04:30 

04:30 we're done looking at all the features,
04:31 

04:31 we can see how it affects a mountain
04:33 

04:33 like this. See, if we plug this in, you
04:37 

04:37 can see that we're getting a really cool
04:39 

04:39 um very recognizable shape. And this is
04:41 

04:41 why I say kind of thermal 2 is that
04:43 

04:43 classic mountain shape where if you
04:46 

04:46 think of a mountain icon in a sense, you
04:48 

04:48 would just think of kind of triangular
04:50 

04:50 shape, right? That's like the universal
04:52 

04:52 mountain uh shape. And I think that's
04:55 

04:55 basically what thermal 2 can really give
04:57 

04:57 you. It can give you very uh very eroded
04:60 

04:60 sharp peaks with a cool talis fall off
05:02 

05:02 at the bottom. So now let's look at
05:04 

05:04 other ways of thermal. Right? So we have
05:07 

05:07 the thermal 2. Um, we have an example
05:10 

05:10 here. I'm using thermal 2 with a slope
05:13 

05:13 inhibition. So, the heavy slopes like
05:15 

05:15 the cliffs are only 50% thermal roaded
05:17 

05:17 compared to the rest of the terrain. And
05:20 

05:20 that gives us this kind of shape. Very
05:21 

05:21 cool, you know, rocky peak with big
05:24 

05:24 talis flows combined with some erosion 2
05:27 

05:27 for the hydraulic erosion. And you have
05:29 

05:29 yourself a very easily art directionable
05:32 

05:32 shape here. Now, you could also use
05:33 

05:33 erosion 2 completely because erosion 2
05:36 

05:36 also has thermal erosion controls in the
05:38 

05:38 form of the shape settings right here.
05:41 

05:41 Erosion 2 is really a powerhouse when it
05:43 

05:43 comes to this because it can give you
05:44 

05:44 extremely realistic results within one
05:47 

05:47 node. However, you do need to give it a
05:48 

05:48 lot of care as it's kind of an ecosystem
05:50 

05:50 where everything ties in together and
05:53 

05:53 you don't really get to isolate one
05:54 

05:54 specific, you know, shape control here.
05:57 

05:57 So, another way of getting a thermal
05:59 

05:59 shape is the thermal shaper node. Uh
06:02 

06:02 yeah, quite obvious. The thermal shaper
06:04 

06:04 is actually more of a filter. Uh it kind
06:06 

06:06 of uses math to calculate what the shape
06:09 

06:09 would look like. It's a very easy and
06:10 

06:10 quick way of getting that classic
06:12 

06:12 thermal shape with those sharp peaks and
06:14 

06:14 that classic triangular look. Distance.
06:17 

06:17 This might be a bit of a weird one. Uh
06:18 

06:18 it is a very mathematical note. Again,
06:20 

06:20 kind of a filter here, but I put it in
06:22 

06:22 here because you can get that cool
06:24 

06:24 triangular shape as well. I just think
06:26 

06:26 that this is a cool way of getting that
06:28 

06:28 shape. Um, and yeah, you can play around
06:30 

06:30 with it and see what you can get. Let's
06:33 

06:33 move down to the actual use cases. I'm
06:35 

06:35 going to create a mountain here. I'm
06:36 

06:36 going to add some hydraulic erosion and
06:38 

06:38 thermal erosion using erosion 2 and the
06:40 

06:40 shape controls. This will give us that
06:43 

06:43 classic, you know, triangular mountain
06:45 

06:45 look. We're going to add some rock
06:46 

06:46 detail with sandstone. And now we'll
06:48 

06:48 just look at all the thermal two nodes
06:50 

06:50 and different settings how it will
06:52 

06:52 affect this this mountain right here.
06:53 

06:53 So, we'll just start with the kind of
06:55 

06:55 basic settings here. a high strength 45
06:58 

06:58 angle no sediment removal feature scale
07:01 

07:01 15. It will remove a lot of the cool
07:04 

07:04 details that we had like the micro
07:06 

07:06 details. However, we do get those nice
07:08 

07:08 cool sharp edges on our convexes and
07:11 

07:11 yeah, it's a very nice effect. However,
07:13 

07:13 you're losing a bit of rock detail,
07:15 

07:15 right? In case you want to keep the rock
07:17 

07:17 detail and just have the actual sediment
07:19 

07:19 added on top of your terrain, you can
07:21 

07:21 use the max setting, the max blend mode
07:24 

07:24 down below. This will just add the
07:26 

07:26 extras we're getting, which is the
07:27 

07:27 sediment buildup. And we will preserve
07:30 

07:30 our rock detail from the underlying
07:32 

07:32 layer. If we only want to see the
07:34 

07:34 effects of the erosion and not the
07:36 

07:36 actual sediment buildup, we'll just
07:37 

07:37 remove all the sediment. And this gives
07:39 

07:39 us this very cool sharp look right here
07:43 

07:43 that we can then add more details on top
07:45 

07:45 of. Now, an accurate way of using this
07:46 

07:46 node in tangent with erosion 2 would be
07:49 

07:49 to use a slope mask to preserve some of
07:51 

07:51 the rock detail. As you can see here, I
07:53 

07:53 am removing all the sediment because
07:55 

07:55 I'll use erosion 2 to actually add very
07:57 

07:57 realistic talis flows. I'm keeping the
07:60 

07:60 feature scale 15. Uh the anastropia is
08:03 

08:03 zero to preserve as much detail. Maybe
08:05 

08:05 50 would be a good angle to start at.
08:08 

08:08 And then we'll take the wear output and
08:11 

08:11 I'll auto level it just to keep it easy
08:13 

08:13 and visible. And we're going to use that
08:15 

08:15 as the precipitation mask in erosion 2,
08:18 

08:18 which is a new thing we have in Gaia
08:20 

08:20 2.2. And in erosion 2 here, I will have
08:23 

08:23 the max filter mode enabled because I
08:25 

08:25 only want to add sediment. I don't want
08:28 

08:28 to have the actual erosion cut down on
08:30 

08:30 my terrain. Like so. I want to keep all
08:32 

08:32 that raw detail. I'm turning the
08:34 

08:34 duration up so we build up more
08:36 

08:36 sediment. I'm turning the down cutting
08:38 

08:38 from 0.25 to 0.1. This will minimize the
08:41 

08:41 amount of down cutting we're getting,
08:42 

08:42 but still cut enough of the terrain off
08:44 

08:44 to actually create these talis flows.
08:46 

08:46 I'm turning off suspended load. I'm
08:48 

08:48 making sure the erosion skill is also
08:50 

08:50 quite small. Um, so we get, you know,
08:52 

08:52 the talis and all these little gullies.
08:55 

08:55 And then I am going to turn up the bed
08:57 

08:57 load and core sediment, find a good
08:59 

08:59 angle and have it there. As you can see,
09:01 

09:01 this works very nicely in conjunction
09:03 

09:03 with the thermal 2 node. We're getting
09:04 

09:04 the erosion, cutting down on the base
09:06 

09:06 layer terrain, making it look like the
09:09 

09:09 actual talis flows are coming from
09:11 

09:11 these, you know, are coming from this
09:14 

09:14 rocky stratification.
09:17 

09:17 making it look like these talis flows
09:18 

09:18 are really, you know, the result of rock
09:21 

09:21 being broken off these cool
09:23 

09:23 stratification details right here. So,
09:26 

09:26 yeah, I hope this is a good introduction
09:27 

09:27 to thermal 2 and the use cases of this
09:29 

09:29 node and just a better understanding of
09:31 

09:31 what thermal erosion does and what shape
09:33 

09:33 you get from it. Hope you guys will have
09:35 

09:35 a good time in Gaia 2.2 and thanks for
09:37 

09:37 watching.