Hello,

Ok a bit lengthy post title but this is the issue.

I'm not sure if what I am trying to do is too much to expect or if this might be an actual bug.

The example hip file is a simplified version of the issue so in a way it doesn't make sense why I am doing this in that context.

There's 4 sources of geometry that are being used as a light source.

If via the switch node I bypass the material applied for all of them, there is no problem in using all 4 lights.

Each light is applied to only one object each.

However, if I apply material to all the geometries that are being used as the light sources, when I go to render it hangs - not take a long time, but it runs for a very short time then hangs.

I can however apply any one of the geometry light(have it Enabled) at a time that has a material applied to it's geometry source - With no render issues.

But never more than one.

Insight to what may be happening is appreciated - Thanks.

see attached.
its the material… try just using a simple shop that sends color to Ce.

Thanks for your response cpb,

For some reason I missed the post and am just seeing it now.

I don't understand why you are saying your approach is the solution.

And this is probably because my example is too simplified and so is my fault.

But in your example you've taken away any applied material to the geometry that is being used as the source for the light.

So in this case it doesn't resolve the ‘issue’, because I need to be able to apply the material and manipulate it from the object being used as a light source.

The thing is, it works if I only do it with one geometry/light combination in the scene - just not more than one combination.

There is a reason I am wanting to do it this way but am trying to keep the post short.

If it wasn't for the fact that it works for one combination, I would just drop the attempt and do a longer workaround for a solution in what I want to do.

Thanks for the input though.

Hi, I've had a quick look at your hip file and found that if you render first and (whilst rendering) use the switches to enable each material, the render will continue to update correctly, eventually showing all 4. However, if you then stop the render and restart, it hangs as you describe. Not sure if that helps with any diagnosis or not. (Does look like a bug to me)

Rob

Hi Rob,

Thanks for the input.

Perhaps I shouldn't have put those switches in there to begin with.

Just wanted to show all 4 work when there is no material, but not when there is.

Would like to have them ‘hardwired’ with materials and to begin with and be able to render.

Ok…simplified the file a bit more. No switches and reduced to two objects.

Either one can be rendered when their geolight is turned on, but not both at the same time.

Using the switches isn't really a workaround but it does highlight that your setup should work and looks more like a bug to me.

ie. I tried referencing those switches to a master switch but it hangs when any more than one material is switched on. It only works when incrementally switching on each material, defeating the purpose of a master switch. So it's not really a workaround, more of an observation that it can render more than one, just not in a way that makes any sense. (bug)

Rob

Accepted as bug:

#86153

Seems like 16.5 is still doing this.

A while back I re-visisted this issue when I saw the Changelogs indicated it was fixed.

It does now work, however using the Renderview panes render button can be a bit glitchy in combination with turning on those extra lights.

Just need to tinker around with it for a bit to get it too work, i.e. save file with Renderview autoupdate on. Re-open file and before anything else(don't enable disable lights first) hit render, letting autoupdate make changes when you turn lights on-off subsequently.

This workflow seems to get me by any glitchiness.

Haven't tested whether render to disk gives same ‘glitchy’ behaviour for results compared to Renderview.