VRay clipper artefacts

[Macker]

Hi all,

I'm trying to take a section through a building/site but I'm getting a lot of artefacts - mostly from foliage it would seem. Any ideas how to remedy this?

Also am I imagining that you used to be able to pick a colour for the section cuts? I'm sure that was the case a while back but I can't seem to find a way of doing it now.

[hermit.crab]

Hi all,

I'm trying to take a section through a building/site but I'm getting a lot of artefacts - mostly from foliage it would seem. Any ideas how to remedy this?

Usually, this is caused by low "max. transparency levels" values. Try upping it a lot.

Also am I imagining that you used to be able to pick a colour for the section cuts? I'm sure that was the case a while back but I can't seem to find a way of doing it now.

The color is taken from the VRayClipper's object color.

[Macker]

Thanks, I'll give that a try.

So is there no way for me to quickly set the section cut as a dark grey for example? I'd have to go through every single material in the scene and set up a multi-sub object material and ID?

[hermit.crab]

You misunderstood me, changing this color (see screencap) should do it.

A better idea would be do directly apply a VRayMtl to the VRayClipper object, though.

[Macker]

Brilliant, thank you!

Increasing the transparency levels to 200 didn't fix it. Trying 500 and can already see the issue persists .

[Edit] Issue persists even with transparency levels set to their maximum (100,000). Any ideas? It's all foliage/forest pro stuff that appears to be causing it.

[Macker]

I just realised it can't be Forest Pro causing it as the issue is visible on the plants in the atrium space, which are placed manually, not scattered by Forest Pro.

[vladimir_krastev]

Hi these artefacts with very complex geometry like foliage that is cut using VRayClipper are a common issue for now. We have a report about this logged in our system under VMAX-12496 for improvement. I will add your thread to it and bump it's priority.

[Macker]

I see that it was logged back in 2017, so I guess it's pretty low priority

https://forums.chaos.com/forum/v-ray...per-forestpack

Thanks for all the help guys.

[yavor.rubenov]

Hi - not that it is low priority - more that I haven't come up with a good solution yet
Clipper itself needs a way to detect if a given point in space is inside some geometry or not. Trees often pose a challenge because if their leafs are single sided geometries - then you can't really say if you are inside or not.
Can you try to exclude those geometries from the clipper ?

[Macker]

Could a solution be to have a check-box that allows the user to not have the clipper fill in the space within geometry?

Then I could have one clipper for the trees with that checkbox enabled (no fill), and another clipper for the rest of the model with it disabled (with fill).

Or an "exclude" rollout similar to the lighting rollout that allows you to include/exclude objects from having their clipped areas filled in?

That way thin geometry could be excluded by the user, yet still sliced so that the section cut works as normal.

[Macker]

...Or have I oversimplified a complex issue?

I had assumed the difficult part isn't the clipping of geometry, but rather the filling the space within?

[yavor.rubenov]

Sorry for the delayed reply.
Actually that is not a bad idea - so thank you for it So far I was looking for some idea that will solve this automatically but maybe some user input would help.

One issue I can think of so far - if we exclude a whole tree from capping - that would exclude the tree's trunk too. I'll have to experiment a bit.

[Macker]

that would exclude the tree's trunk too. I'll have to experiment a bit.

I'd take that fix at this point!

Perhaps the non-filled geometry could have an outline x Pixels wide (like VRayToon/Edges tex)?

[Macker]

Is this something that is likely to make it into the nightlies any time soon?

[yavor.rubenov]

Sorry - not very soon.