Iray section planes for Blender?

DrGonzo62

Hi,
Is there a funtionality in Blender similar to DS Iray section planes to cut down on render times?
An add-on maybe?

Thanks!

Padone

booleans ?

DrGonzo62

Padone said:

booleans ?

As in per object you want to hide from the renderer?

In DS you just add a section plane and all geometry behind that plane will be hidden from the renderer.
I didn't get far enough into Blender to know if you can do a bool on a collection or not, but I would be surprised if you can.

Padone

Yes you can do collections on booleans, if you just look at the modifier you see the options.

DrGonzo62

The problem for me is, that any mesh lighting gets hidden as well.
So I can no longer just render a section of a scene and composite it afterwards, since the lighting no longer matches.
Something you can easily do in DS.

Wolfwood

As strighforward as section planes i don't know. But a search on the subject pointed me to what appears (haven't tried it) to be a clever way to use geometry nodes to do something similar:

https://blender.stackexchange.com/questions/284371/hide-instances-outside-of-area

 

DrGonzo62

Wolfwood said:

As strighforward as section planes i don't know. But a search on the subject pointed me to what appears (haven't tried it) to be a clever way to use geometry nodes to do something similar:

https://blender.stackexchange.com/questions/284371/hide-instances-outside-of-area

 

Thanks for the feedback.
DS section planes can hide geometry from the Iray render engine, but retain the light emitted by that geometry (clipping lights on or off).
Like part of a ceiling emitting light. You can hide the ceiling, but still keep the light provided by it.

 

crosswind

You may try using Clipping Plane in Bonsai's BIM extension. It's a free extension you can directly install in Blender.  https://docs.bonsaibim.org/quickstart/installation.html

The clipping plane can be found under Quality tab.. It's still an experimental function but it'll work.

DrGonzo62

Looks interesting, thanks!

Kitsumo

This isn't the exact same as an Iray section plane, but you can kind of get the same effect.

DrGonzo62

I'll check that out, thanks!

DrGonzo62

crosswind said:

You may try using Clipping Plane in Bonsai's BIM extension. It's a free extension you can directly install in Blender.  https://docs.bonsaibim.org/quickstart/installation.html

The clipping plane can be found under Quality tab.. It's still an experimental function but it'll work.

Hi,
I played around with this today, and while this clipping plane works pretty much the same as an Iray section plane, it did not reduce render times as far as I could tell.
While geometry is hidden behind the plane, it seems that it still gets fully considered in the render, it's just no longer being displayed.

For example, one of my scenes that takes 13 minutes to render in DS, will take only 3 minutes with a section plane behind the camera, and looking exactly the same.
I played around with camera culling in Blender as well, but I couldn't really achieve the same reduction in render times that I can get using Iray.

Richard Haseltine

DrGonzo62 said:

crosswind said:

You may try using Clipping Plane in Bonsai's BIM extension. It's a free extension you can directly install in Blender.  https://docs.bonsaibim.org/quickstart/installation.html

The clipping plane can be found under Quality tab.. It's still an experimental function but it'll work.

Hi,
I played around with this today, and while this clipping plane works pretty much the same as an Iray section plane, it did not reduce render times as far as I could tell.
While geometry is hidden behind the plane, it seems that it still gets fully considered in the render, it's just no longer being displayed.

For example, one of my scenes that takes 13 minutes to render in DS, will take only 3 minutes with a section plane behind the camera, and looking exactly the same.
I played around with camera culling in Blender as well, but I couldn't really achieve the same reduction in render times that I can get using Iray.

Iray section planes are actually designed to work the same way, as far as I know their default behaviour is to hide geoemtry from the direct camera view but leave it present for shadows, relfections etc. so that ytou can see into an enclosed space but still have it render as if complete. Daz chose to make them work the other way by default, so that the clipped items are completely hidden, as peoiple seemed most interested in the feature as a way to get light into closed spaces.

DrGonzo62

Thanks for that explanation, Richard!
I often render an animated object fully enclosed by 5 or 6 section planes for later compositing over the scenes static background image.
I couldn't render longer animations without this feature, even with 3090 cards.
 

crosswind

DrGonzo62 said:

crosswind said:

You may try using Clipping Plane in Bonsai's BIM extension. It's a free extension you can directly install in Blender.  https://docs.bonsaibim.org/quickstart/installation.html

The clipping plane can be found under Quality tab.. It's still an experimental function but it'll work.

Hi,
I played around with this today, and while this clipping plane works pretty much the same as an Iray section plane, it did not reduce render times as far as I could tell.
While geometry is hidden behind the plane, it seems that it still gets fully considered in the render, it's just no longer being displayed.

For example, one of my scenes that takes 13 minutes to render in DS, will take only 3 minutes with a section plane behind the camera, and looking exactly the same.
I played around with camera culling in Blender as well, but I couldn't really achieve the same reduction in render times that I can get using Iray.

I don't think that clipping plane has this feature of like Iray section plane... as cycles engine is differenct from iray engine after all. But there're quite a few ways to speed up rendering in Blender and lots of tutorials there on youtube.

You may try those tricks as needed ~~