Understanding discaplacement, HDRI loader & tiled exrs

[Neilg]

I have a scene with some huge 40k wide maps - they have been converted to tiled exr and are all using the hdri loader. For the diffuse texture this looks ok, is seemingly full res and has low memory usage. The displacement however appears to be using the same resolution map as what is displayed in the viewport, and nothing I can seem to do will sharpen it up. Filtering in the displacement modifier does nothing, the interpolation & filtering sections in the HDRI loader do very little, and dropping edge length doesnt do much either. Object has been subdivided to be 500k polys, doesnt make a difference.

This is a render of the displacement on a grey object with edge length set to 1, and below is the displacement map it's using.



Cant figure out what i'm doing wrong here, any tips?

One other question - I usually like to render most of my textures with filtering turned off so they're sharp and vrays AA can clean it up. Is this not an option in the hdri loader? The maps get very blurry at glancing angles to the camera and none of the filtering options sharpen it up anywhere near as much as setting it to 'none' would.

[Neilg]

Here's a better shot showing that the displacement is reading a much lower resolution version of the map. Same position and angle as the examples above.

[damaggio]

Is this 16 bit? 32?
You could take into World Machine and regenerate a 32EXR 16K resolution.
Your texture filtering is correct, leave it off.

[Vizioen]

You say you're using edge length of 1. But why not use 2D displacement as you're using bitmaps? Or doesn't 2D work with tiled EXRs?

[Neilg]

Is this 16 bit? 32?
You could take into World Machine and regenerate a 32EXR 16K resolution.
Your texture filtering is correct, leave it off.

I used the vray script to generate the file from a 16bit source tiff.
I just used a tiff in the end - not using the hdri loader. It doesnt use too much memory and looks outrageously sharp/detailed.

Vizioen - I never use an edge length of 1, that was just to illustrate that changing it doesnt affect the resolution of the map it's pulling. My map is 40k wide and doesnt tile, I dont think 2d displacement is the most efficient way to render that.

[Vizioen]

Just taking a super wild guess here as I have never used tiled textures, but there's this option in render settings called tiled texture options and the cache size has a default of 4000MB. Could it be that this is limit is exceeded and Vray uses some kind of mip map of the tiled EXR instead of the full resolution?

[Neilg]

Are you sure thats not a GPU only setting? I cant find that in 3.6.

edit: nevermind, found it! 4gb should have been enough - with all other maps disabled the displacement still does this. none of the other maps are impacted. It was just not loading anything more than the lowest quality version.

[TomGore]

Have you solved your problem?

[Neilg]

Nope, switched to tiff for the displacement. Tiled maps & HDRI loader works great for every map which is 'visible', but using it in a displacement map doesn't seem to be able to load anything but the lowest res layer.

I finished a test render of it last night - https://www.instagram.com/p/Bma9w8GHgjQ/