Rendering Tips and Lighting in Revit 2018.2

[JohnCameron1116]

Hi Viveka_CD,

I have what might be a related question.

In Revit 2018.2 I am rendering the same scene to show various lighting scenarios, so there are several artificial light sources in the model. I have grouped these for scene setting and balance purposes, as well as edited the colour temperature to get the artificial lighting effect I'm trying to convey.

All good with "interior artificial" and "interior sun and artificial", but for some reason with "interior sun only" some, but not all, of the lights remain illuminated.

should be sunlight onlysun and artificial light

The image on the right is both sun and artificial light. Note the pendants, table lamp and the kitchen splashback lights are on. The image on the left is sunlight only. The pendants, table lamp and splashback lights are off, but the can downlights and strip lights remain on.

I have opened the render dialogue for light fittings and de-selected all lights before changing to sun only, but it makes no difference.

Any suggestions would be most welcome.

[Viveka_CD]

Hi @JohnCameron1116

Can you try updating to Revit 2018.3 and let me know if the issue is resolved?

Regards,

[JohnCameron1116]

Hi @Viveka_CD

Thanks for the quick reply. I have updated to 2018.3 but this did not solve the problem.

Here is a further experiment:

Interior artificial only - lights off except for studio lights in background

After updating to 2018.3 I ran several renders with previous lighting settings, with the same outcome as 2018.2.

The image above shows a new "interior lights only" render (2018.3) with all lights (except 3 studio lights in the background) turned off (unchecked in the lights list). I see that the table lamps are completely dark, as they were before, but the pendants, strip lights and downlights render as if they are on, but no light is being "emitted" to render the scene. This makes me wonder about the properties of diffusers in light fitting families, as all of the problem fittings have them, whereas the fittings that are working properly do not?

[barthbradley]

Could a Self-Illumination material be the reason behind why the lights are "on"  in a sunlight only rendering? 

Just wandering by...

[JohnCameron1116]

@barthbradley good call!

I've just checked and all the problem families had self-illumination checked on for the glass diffuser material. I un-checked self-illumination in each family, re-loaded and re-ran the render. The pendant fitting came good, but the downlights and strip lights did not. This seems strange because the materials properties were the same in all 3 families, yet only one family changed its render performance.

I further checked each family to see if I could find any other material/element with self-illumination properties, but there were none that I could see.

[Viveka_CD]

Hi @JohnCameron1116

Can you re-render with just the strip lights on and let us know how it shows up?

Are you using a downloaded strip light object or designed a custom light or you have nested electrical connectors?

Also, check Best Practices: Render Performance and Lighting

You are welcome to share a file with us to test further.

Regards,

[JohnCameron1116]

@Viveka_CD I have attached the Revit model. It is just a "set design" exercise to explore scenarios, including lighting strategies, hence the importance on accurate rendering.

All lighting families are from Revit libraries. The only customisation is turning off the self-illumination properties in the can, pendant and strip light families.

Maybe you can try some renders and see what the outcome is?

@barthbradley this might also interest you?

[barthbradley]

@JohnCameron1116: Funny. Reminds me of the Best Western Lodge in Lake Tahoe. This looks a like the room they serve breakfast in. All your rendering need now is those polished tureens on the counter that keep scrambled eggs and sausages warm.  

So, what's the deal with Self-Illuminating materials? I thought you didn't want that.  Just curious.

Nice renderings. Thanks for sharing. 

[JohnCameron1116]

@barthbradley Ha ha! It is actually for a nursing home scheme - meant to be "homey" rather than clinical, but it is hard to get past the ol' Best Western look...

OK, this self-illumination thing is doing my head in!

I just checked all the light fittings again and the self-illumination was turned on, but I had previously edited them to be off. So, I opened the families again, un-checked self illumination for the diffuser material, saved them as a new family, loaded them into the project to replace the originals, ran the render - same problem. So, I opened the newly created families again, and guess what, self-illumination was ON!

It seems that for some reason the self-illumination property reverts to "on" when loaded into a project. That explains the rendering problem.

Can you please try editing these families to see if the persistence issue happens for you?

[barthbradley · Accepted solution]

 You don't need to go back and forth between project and family. You've got parameters. Just change the material settings in the Project. The family's material parameters are associated to the Project's materials. 

[JohnCameron1116]

@barthbradley That worked! You're a legend!

@Viveka_CD - Problem solved by Barth Bradley.

Lights out!

[Viveka_CD]

Hi @JohnCameron1116

That's awesome. Glad to hear your issue is resolved.

Nice model and idea!

Good luck with the project!

Thanks @barthbradley for taking a stab at this one 

Regards,