Point lights

[cobrien]

Hello,

I can't get point lights to work with vray, all the other light options are fine but not point lights. I've attached a file to show what I mean.

Any ideas?

light test.fmz

[Andrew West]

Forget about point lights.  They don't work.  Change it to a sphere light and be VERY careful about your intensity and camera settings.  They are very difficult to control.  I would seriously suggest you use mesh lights with v-ray and if I need the light to be visible I do that through emitter materials at the source.  Add the glare effect in Vray and it is pretty convincing.  

Edited February 18, 2021 by Andrew West

[cobrien]

Thanks again Andrew. There have been a few things I've spent ages trying to get to work only to find out they don't work! It makes it hard to know when to give up on something.

I'll give mesh lights a try, thanks.

Have you had any luck rendering vray images in Imager? I can render vray images but I can't access vray settings in Imager & even with Link Image Options & Link Display Options selected when adding views it doesn't bring them in. For example, if I have Render Elements enabled in FZ (& rendering fine in the Frame Buffer) then I try rendering the same file through imager it won't enable Render Elements.
Is this just me?

[Andrew West]

You are experiencing one of my great frustrations with Form.z.  Namely, things that should work but don't.  Knowing when to abandon something and find another "work around" is key to keeping your sanity.  For me sometimes that "work around" means literally going to another program rather than finding another tool.  V-ray proxy, caustic affects, scene files and such are  perfect examples of things that I abandoned.  Thankfully, they are aware of these issues and they are working on them.  I learned this week that in 9.1 Reference files are now working properly!   

As for your imager issue I find that V-ray is so fast at rendering I don't ever use it.  It does not surprise me that you are having issue with it.  The integration might not be complete yet.  I have a similar issue with rendering via GPU where certain render elements don't work at all.  The most important one being Alpha Channels.  I don't know anyone who can work without that function.  Good luck and really stick to mesh lights for your scenes.  They are great to work with and much more predictable.  Just don't let them touch any objects in your model.  

[cobrien]

Hello,

Support got back to me re Point lights & the intensity needs to be greatly increased, to 1000 or more! It then shows up as normal.

Seems a bit weird to me that the intensity slider goes from 0-100 but you need to type in 1000 or more to have any effect. The Cone light slider I find annoying the opposite way, it goes from 0-100 but you need to make adjustments in 0.1 increments or your whole scene gets blown out. Mine is typically set between 0.8 & 1.5.

[Andrew West]

You are exactly right.  But like I said, when using Vray as your render engine you will find mesh lights much easier to control and more predictable.  Doing hundreds of test renders as I adjust my other types of  lights is a waste of time and too frustratingly arbitrary.    If only Vray had what Maxwell has,  namely Multilight.   Man was that nice.  I am still holding out hope that the new version of Vray may be out before too long.  I think that the lighting systems will change again.  

[johnalexander1571]

Hi Cobrien,

I wanted to share my easy lighting Vray workflow, at least for interiors. One thing first, point lights are bad because in the real world, light never comes from a tiny speck. If it did, you would see bizarre shadows. Light always comes from a surface that has a size, and this makes shadows get blurrier at the edge the farther they are from the subject. Natural shadows are one of the most important for nice renders.

SO, Andrew is right, mesh lights are the correct solution. I cannot bring myself to this, I don't know why. I only use the VRay plane light, and the VRay sphere and keep the old workflow. I put the plane lights in the windows, using the translation tools (not the light controls). I throw the VRay spheres in for fills and even general illumination. I make the lights invisible, and hide them form reflections as needed. I turn the plane lights down to 5 (they start at 30), also the spheres. One nice thing about this method is the values for the intensity make sense and respond to intuitive numbers. Plus once you have one set up, you just duplicate them and move them around.

This gives you the old feel of working, but the advantage of the VRay render. I find I do the same in Arnold.

 

[johnalexander1571]

Last image I did last week. I did stray from VRay spheres and used IES for the lamps. One VRay plane light in the ceiling. There is an emitter material on the screen map.

 

All modeled in formZ and rendered in Vray.

[johnalexander1571]

Sorry, the resolution on the posted image is too low. It is really 5000 pixels wide, the moire patterns are not there.

[johnalexander1571]

Here is a link to the whole image.

https://www.artstation.com/artwork/rAyE4a

 

[cobrien]

Thanks for taking the time John. I haven't had much of a play around with plane lights but I'll give them a go. What do you mean by 'using the translation tools (not the light controls)'?

You render looks really great!

[johnalexander1571]

Yes, I always aim a plane light by translation only. I seem to recall lights acting strangely if I used the pointy end or any other means to aim a light. Usually the plane goes in a window or up on the ceiling. I use the standard rotate and move tool looking from the two angles. I do have to type in the size of the plane in the properties. I only use translation tools to aim IES lights too. Just makes it easy. Of course, sphere lights don't have aiming issues which was part of the ease of use. I never use cones.

It is probably easier to build the correct geometry and assign an emitter material or do mesh as Andrew does, now that I write out my process. Mine is just the old RZ way.

Edited March 3, 2021 by johnalexander1571
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