Displacement issue

[zhty96]

Hi there,

i am having problem when I use coronadisplacementmod with 3ds max. it is about a 600m x 1000m landscape scene. i've applied a very simple jagged rock material to the polysurface and a additional displacement map (see in the attachment) to coronadisplacementmod. the uvw map size is set to 80m x 80m as plane.

when i run the rendern i always get this very weird results with those "blocks" or "steps" effects in the front scene. it seems to look okay for the scene far away but not sure if i increase the resolution it may have the same problem like the front scene.

i've already tried the displacement sceen size and world size option in the performance setting but the problem still exists. and the RAM comsumption seems to be okay: about 15 GB used of 64 GB.

someone having any ideas about this?

i'm using 3ds Max 2023 and corona Renderer 8.

[romullus]

Hi,

Try to load your displacement texture with Corona bitmap node instead of native bitmap. If that won't help, then it's likely that your displacement texture has too narrow dynamic range, i.e. saved to 8 bit format, instead of 16 bit, or 32 bit.

[dj_buckley]

Do those stripes follow the edges of your geometry by any chance?  Are you able to screenshot the viewport with a shaded wireframe?

Pretty sure this is the same issue (or similar) that I've banged on about for years regarding 2.5D displacement in Corona - edge based artifacts.

The texture used does look quite low res too, but that doesn't negate the artifacts, they'd still be there with a higher fidelity texture.

[zhty96]

Hi Romullus and jd-buckley,

very thankful for your quick reply!

to romullus:
i tried to save the map into  a 8bit  format and also using the coronabitmap node but it seems not gonnan work properly as well. and i tried to use the same displacement map but using vray engine and it could be already rendered correctly so i think the problem may be not about the too narrow dynamic range.

and to buckley:
as you can see in the attachment theose stripes actually not following the "construction" edge of the object but following the world xyz axis. i tried to align the view to face the y direction (seen in the second picture) and the stripes are all along the x axis.

accidentally i solved this problem by creating a completely new polysurface and roughly made it like the geometry before. now corona could rendern it very well to some how. I am not quite sure about the logic behind this. But for a better unterstanding:
the whole oringinal geometry (about 5km with around 600k polys) was exported from a GIS software and edited in Rhino. after imported into 3dsmax i selected an area (600m x 1000m) and detached it as a new object. after applying the material i mentioned before and also the displacementmod the problem with those stripe effects come up. dont know if there is something wrong during these processes but it seems to be the problem of the geometry.

thanks again for all of your help again! and I will try to figure out what was going wrong. :)

[romullus]

to romullus:
i tried to save the map into  a 8bit  format and also using the coronabitmap node but it seems not gonnan work properly as well. and i tried to use the same displacement map but using vray engine and it could be already rendered correctly so i think the problem may be not about the too narrow dynamic range.

No no, saving displacement texture to 8 bit file is the last thing you would want to do! You should always save it to at least 16 bit file or higher, but if you already saved it to 8 bit, then re-saving it to higher bit depth will not help.

accidentally i solved this problem by creating a completely new polysurface and roughly made it like the geometry before. now corona could rendern it very well to some how. I am not quite sure about the logic behind this. But for a better unterstanding:
the whole oringinal geometry (about 5km with around 600k polys) was exported from a GIS software and edited in Rhino. after imported into 3dsmax i selected an area (600m x 1000m) and detached it as a new object. after applying the material i mentioned before and also the displacementmod the problem with those stripe effects come up. dont know if there is something wrong during these processes but it seems to be the problem of the geometry.

It's quite possible that something was wrong with your original geometry. If you want to investigate this, you can open a support ticket and send a scene for Corona support team to inspect it. You can do that here: https://support.chaos.com/hc/en-us/requests/new