Author Topic: Displacement problem  (Read 1666 times)

2022-01-14, 15:40:02

Martin Janousek

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Hi,

this is old issue for our studio appearing since the beginning of 2.5 displacement. We often get 3d models from clients made in Archicad or Sketchup, with a lot of different (sometimes not correct) geometry. And using the new displacement we have issues with strange triangle artifacts as if the geometry was somehow broken or something. Usually we resolved it by using the old 3d displacement. But with the latest Corona this in no longer possible.
Sometimes we remodel the specific geometry parts but it's extra time for us. Is there any effective way to deal with this? Thank you!

2022-01-14, 15:57:10
Reply #1

Frood

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Never underestimate the power of a well placed level one spell.

2022-01-14, 21:59:04
Reply #2

Martin Janousek

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Maybe this helps:

https://forum.corona-renderer.com/index.php?topic=34746.msg191376#msg191376


Good Luck

Hi, thanks for the reply. Unfortunately this subdivision method doesn't always work the best. Also would prefer not to do changes to geometry if it's possible to deal with this through the material/renderer itself. As it was possible earlier with proper 3d displacement method.

2022-01-18, 11:34:52
Reply #3

Bormax

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Hi
In this kind of situation I use Grider script to subdivide exported from Archicad mesh
http://www.scriptspot.com/3ds-max/scripts/grider

2022-01-18, 13:57:11
Reply #4

dj_buckley

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I've highlighted this before and will highlight again.  Removing the old displacement was a terrible move.  It fixed a lot of problems with displacement that are evidently still there, like the one highlighted in this thread.  Subdivision is not the answer.  It's ugly, messy and adds uneccessary geometry to heavy scenes.  It looks horrendous on clay wire renders too, and they're used all the time for previz in a lot of arch Viz workflows.  Currently displacement only works on ultra clean meshes, terribly subdivided meshes, or meshes so dense that you can't see the problem.  Its madness to me that the old method was removed - because it worked.  Simple as that.  Now it's gone, you can't fix these current issues without workarounds.  That's a step backwards, not forwards

2022-05-13, 11:58:54
Reply #5

Martin Janousek

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Hi, is there anything new with this? It's constantly causing us troubles. Every time we get model from client (last time model from Revit) we have these kind of issues with broken displacement. For is remodelling the whole geometry really isn't an option due to the scale of these projects. With the old "3d" displacement it worked just fine. Would it be possible to somehow made it available again (in form of some legacy checkbox)?

2022-05-16, 00:02:32
Reply #6

frv

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Hi, I posted a thread about this problem, in my case the displacement mapping and color maps did not match. Anyhow, I also see the displacement problems you mentioned.


I just did an apartment building of over 25 stories in brick (masonry) in CRv9. The geometry was a mess and so got lots of displacement problems like the triangles you showed.

I finally gave up and rendered the project "as is" at a high res of about 3600x4200 and the displacement setting 1 pixel. Results where not as bad as what I saw at lower resolution.

The models I work with are mostly done Vectorworks. When I do them myself I can model the same building at about 20% in terms of Mb's and a lot cleaner to work with a lot less artefacts in the displacements. I am surprised to see though that the messy models of my co-workers do perfectly well in Lumion.

The current displacement problems almost exclude CR for archviz.

2022-05-18, 20:49:28
Reply #7

Martin Janousek

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In the last project we had to turn off the displacement of the bricks completely.. Crops for comparison. We've had displacement 1px settings.

2022-05-19, 02:08:41
Reply #8

PROH

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Looks like flipped faces are causing the problem.

2022-05-19, 08:30:09
Reply #9

davetwo

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yeah - displacement map looks inverted to me too.
Invert the disp' map if you cant fix the normals

2022-05-19, 11:27:50
Reply #10

maru

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In the last project we had to turn off the displacement of the bricks completely.. Crops for comparison. We've had displacement 1px settings.

This looks like an incorrect texture used for displacement and too strong value. In this case, I suspect that bump would actually be a better choice than displacement.

But anyway, if anyone is having some problems with displacement (like the triangular artifacts in the 1st post here or anything else) please feel free to contact us with your files (preferably simplified) here: https://support.chaos.com/hc/en-us/requests/new

Thank you!
Marcin Miodek | chaos-corona.com
Chaos Corona Support Team Lead | contact us

2022-05-20, 01:34:13
Reply #11

frv

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Displacement is a problem in Corona render. I have images with gravel for pavement and you always see fine straight lines every where. I also see it in images posted in the galleries. In Corona render its best to stay away from displacement for architectural work. But without displacement the photoreal image quality suffers a lot.

But displacement for masonry, gravel etc works better at very high resolution rendered images with pixel settings at 1. I am not sure if you can set a finer pixel setting like 0.5. But no matter what you do you get all sorts of artefacts that I think where no problem a while back. The displacement textures for masonry are usually rather bad as well. I think things look better if you have high res displacements maps as well with not all that harsh gradients between what needs to be displaced and what not.

I attached an example of the struggle. This was rendered at high res but the masonry still has artefacts. The same displacement texture and model in Lumion is completely hassle free.

The pavement btw is by the Corona material library and show less artefacts.
« Last Edit: 2022-05-20, 01:40:12 by frv »

2022-05-20, 10:23:24
Reply #12

dj_buckley

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Glad I'm not alone on this.  I'm now at a point where I avoid displacement where possible because it's so unpredictable and prone to an array of artifacts

2022-05-20, 10:53:47
Reply #13

frv

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Indeed it is a problem but good displacement maps are as well. It will take a lot of experimenting to find out where the problem is exactly. Thing is that other renderengines suffer much less and Lumion has no problem at all.
I will also take a look at Redshift, maybe its better for displacements. A lot of asset developers have started to provide for Redshift ready stuff as well.

If displacement keeps being a major issue I probably have to move on. Can't spend half of a job on getting displacement on track.

2022-05-20, 11:52:18
Reply #14

maru

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It seems that there is some real issue here, so please contact us with your files (preferably simplified) here: https://support.chaos.com/hc/en-us/requests/new
It is possible to attach files in the contact form itself, but you can also skip this step and we will ask you for your files later with a special upload link.
Marcin Miodek | chaos-corona.com
Chaos Corona Support Team Lead | contact us