work-around for slow PT reflection calculation

[Dune]

Okay, thanks. So in fact I need a really finely displaced obj for the frontal area. I'm trying with a simple lowpoly flat obj atm. See how the bump comes out. The try and render an obj...

[Kadri]

... If it's bump, I might as well project all my shaders onto an obj sheet, as the ground is pretty much flat, apart from the rectangular pit. I'll try that. It's a huge difference in render time indeed, and I gather from your information the long rendertime is from micropoly rendering versus the shorter time for obj 'bump' rendering. Very interesting.

But good that you asked. I accidentally used all the displacement from the original landscape on the object too, instead of only using the colour and reflection node. So the looks from the curious more detail was from there. Not sure if that detail was from displacement of the polygons or what not (maybe bump?)... But when i only used the colour and reflection node on the OBJ object the render time was even faster; 1 minute and 15 seconds. The image looks nearly the same as the standard landscape too now.

[Kadri]

Curious if pathtracing will be any different on your test.

[Dune]

Yes, that figures. Perhaps the calculation of the bump on obj will take just as long as calculation of real micropoly displacement. In that case a fine obj is needed indeed, for just color projection. I'll do some experimentation.

And yes, PT is what I intend this for, because SR renders pretty fast, even with the small displacements and reflections.

[WAS]

Resolutions of heightmap and objects is waaay less detail than an actual TG terrain. This is why secondary displacement doesnt play well with erosion shader, or imported heightmaps because the actual subdivision of the area doesnt have as much detail. Ive mentioned this for years that using heightfield generate on a scene renders much faster than default terrain. But that's because its simplified and you can see that trying to do lateral displacement or heavily changing up the displacement

[Kadri]

Resolutions of heightmap and objects is waaay less detail than an actual TG terrain. ...

Yes. That was the reason i was surprised to see more detail in the OBJ scene. My fault...

This is the proper  version here. But as i said this time the obj landscape rendered even faster.

Standart: 27 minutes 33 seconds
OBJ      :  1 minutes 16 seconds

Even the bad lined rendering part in the middle is the same this time.

[WAS]

Im doing a pT test with heightmaps here. Currently timing TG terrain.

[WAS]

Time difference is in the quality with heightmaps, so may not be the best method. Obj seems quicker.

[Kadri]

What were the render times and resolution of the heightmap?

Did you used it as a heightmap? There could be some fractal detail if so...
How about using it only as an image displacement?

[WAS]

That is true. I did not save it. I just let TG take control of the 10k area as a 1000 point heightfield.  Ita bakinf a 8k heightmap so ill save that and try it as a image.

[WAS]

I tried saving the simple 8196x8196 10k area as a EXR, but it just loads as black terrain, or as fed to a displacement shader, no surface, just sky...  Tried playing with disp and offset with surface layer, dunno what's up.

Starting to think something is wrong with TGs EXRs and may explain my opening issues and stuff.

[Kadri]

I just thought about it a little. I don't know what the result will be with your next test Jordan.
But as Ulco said in the post in the first page maybe the difference is in which way Terragen renders micropoly detail and the other kind of objects.
If so, using heightmaps and or image displacement maps will only get a boost from using less detail and less number of nodes  in the scene. It might be faster but maybe not as fast as using an object.
Curious...

[Kadri]

I tried saving the simple 8196x8196 10k area as a EXR, but it just loads as black terrain, or as fed to a displacement shader, no surface, just sky...  Tried playing with disp and offset with surface layer, dunno what's up.

Starting to think something is wrong with TGs EXRs and may explain my opening issues and stuff.

Hmm...sucks. I can't help too. I can not use pathtracing...

[WAS]

It's faster because of the detail of the mesh of the planet at the heightfield area.

As I've stated several times, you could have hundreds of shaders slowing TG down, or just a few, but as soon as it's a heightmap and simplified, it's far faster. At the cost of geomerty detail. Hence adding displacement, or lateral dispalcement, etc, is just a mess of folds and tears. Applying displacement to Classic Erosion of Heightmaps is a pain.

PS loading a ter seems to work fine but not sure of impact. Rendering now.

[WAS]

8196x8196 points at 10000x10000m as a TER is faster than 1000x1000 points at 10000x10000 meters (as a generate), however it seems to interact with the shaders strangely.

Still no [real] detail from original terrain. Trying smaller 1000 area now.