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Re: Unnaceptable Revit Workflows - Light and Materials

PostPosted: Mon Jun 11, 2018 12:49 pm
by SamuelAB
Any reply on this? This is one of the last things holding up the plugin for Revit.

Re: Unnaceptable Revit Workflows - Light and Materials

PostPosted: Tue Jun 12, 2018 12:03 am
by face_off
Sorry - I have been tied up with the Octane 4 version of the plugin. I will take a look later today.

Paul

Re: Unnaceptable Revit Workflows - Light and Materials

PostPosted: Tue Jun 12, 2018 11:29 am
by face_off
Any reply on this? This is one of the last things holding up the plugin for Revit.
I had a look at your scene.

Lithonia and Selux simply showing up as normal geometry in the Revit API. Neither has a material - so it is not possible to associate an Octane emitter material to those bodies. If I render in the Revit renderer, it doesn't seem to pick these objects up as light sources either. Perhaps I am misunderstanding what those geometry bodies are? If you assign a material to these bodies, then edit the Octane Material, you can setup a Diffuse Emitter material with an IES distribution as per the manual.

Similar with ETC-ProMulticell - As per above, although I can see the light angle is set to 30 degrees - but no other light details.

If I edit the Family, I don't get any additional information.

Paul

Re: Unnaceptable Revit Workflows - Light and Materials

PostPosted: Fri Jun 15, 2018 2:49 am
by SamuelAB
Your reply is a bit unclear. Lithonia and Selux are the name of the brands of light fixtures I modeled into light fixture families. Are you referring to the photometric web inside inside each family or the family geometry?

The shape you are attempting to get is referred to as a photometric web. It does not have a material since is not meant to be visible. Perhaps you shounld contact the API developer to learn hos to get access to it in the manner you need?

https://knowledge.autodesk.com/support/ ... 1-htm.html

What we assign to thephotometric web is a distribution. For serious lighting, we use IES files. For fake and fast light, there is also
-Spherical
-Hemispherical
-Spot
https://knowledge.autodesk.com/support/ ... 6-htm.html

Each of these non-photometric distributions are fake and non-realistic.

If you look into the family's parameters you will see the following:
-Initial Intensity (lumen value): Octane uses Watts for some reason, but there is a conversion ratio
-Angle of rotation (can only rotate in one direction)
-Light Symbol Size. This will be a radius for a sphere or lenght/width for a rectangle or lenght for a line (Emit from diameter, emit from lenght, etc)
-Photometric Web File: This is the IES file if you choose a photometric web
-Light Loss Factor: This number is actually an efficiency percentage menat to lower the final power of the light. So 0.85 LLF means you will only use 85% of your initial lumens because of inefficiencies like an old weak lamp or dusty lenses. So you should multiply your initial lumen value by this percentage.
-Initial Color: This is the color temperature in Kelvin

To see these parameters, you have to go into the Type Parameters of the family. The icon is a blue square divided in four, at the top left of the screen in the family editor.

If you can detect the base point and orientation of the photometric web / light symbol, then you can reconstruct it with the shape parameters to create a temporary geometry that Octane needs to emit lights.

I'd be happy to show you around the interface and how lights work by video conference.

Re: Unnaceptable Revit Workflows - Light and Materials

PostPosted: Wed Jun 20, 2018 12:36 pm
by face_off
The Revit SDK does not seem to readily provide light geometry, and even if it did, Octane requires an emission geometry to emit light (as is the case with real light emitters), so the concept of point lights just does not translate. Other plugins I support have implemented some translations of lights from the host apps to Octane by creating geometry emitters when the Octane Viewport is opened. However this is not a trivial task, and the host app where this has been done provide all the necessary light information, whereas Revit does not. So, "yes" we may be may able to implement better support for Revit lights, however it is a substantial coding task, and not something that can be achieved whilst there is so much work to be done building Octane 4 support into the plugins.

I am not sure what else I can say on this. The plugin does not have the functionality that you require, so you need to either accept that limitation, or choose another solution.

Paul

Re: Unnaceptable Revit Workflows - Light and Materials

PostPosted: Sat Jun 23, 2018 11:52 pm
by SamuelAB
Regarding the light geometry, I am reading the opposite. It seems people are trying to export the light, without the Light Source Geometry. Would it not be easy to export just the light geometry and use that?
https://forums.autodesk.com/t5/revit-ap ... -p/7499054

My workflow to Revit to Octane with lighting right now is:
Export FBX from Revit, Link in 3ds Max. All lights are present (but usually rotated 90 degrees and often using wrong units). Then I can use the VRAY converter to convert all lights into Octane lights. No idea why, but it works and the Octane converter does nothing for these lights.

Most users won't want to do this to try a renderer they never heard of that works in a way they never used (nodes), they will just keep using Vray directly in Revit.

I am guessing that the Octane plugin is not very popular for Revit. I never hear of its use in the architecture industry.

I'm not sure if it's really worth the effort building Octane 4 support, for a plugin that does not support lighting.

Re: Unnaceptable Revit Workflows - Light and Materials

PostPosted: Sun Jun 24, 2018 1:50 am
by SamuelAB
Also, I would prioritize support for rectangular and circular lights with photometric files. All other light sources are a bit sketchy.

Lines theoretically have no thickness and point at theoretically infinity small.
Non-IES lights are lies.

Re: Unnaceptable Revit Workflows - Light and Materials

PostPosted: Tue Jul 31, 2018 6:25 am
by JNDesign
SamuelAB
Try having a family that you can swap with
eg
If I have a light instance family, I use a flat geometry say 50mmx50mmx2mm (unfortunatly 2mm is thinnest you can create in Revit)
to this family, I would apply ies files and make the opacity 0
This works for me on any type of light.

As for Octane, its the fastest renderer on the market. I know logic is slightly different to max vray etc but if you can get your head around the workaround, the programme will pay back in 10 fold albeit with speed at least.
We have 12 Titans water cooled across 3 machines and our renders just gets done very very fast

Paul.... dont give up
please work on V4 for revit, .....we love your work,
we have won lots of work due to the render capability and capacity of your plugin so thanks in advance for the new v4 release.

Re: Unnaceptable Revit Workflows - Light and Materials

PostPosted: Thu Nov 29, 2018 1:38 am
by face_off
Also, I would prioritize support for rectangular and circular lights with photometric files. All other light sources are a bit sketchy.
What do you mean by a "rectangular light" please? I don't see these as options in Revit. My understanding is that light sources come from the Family->Lighting->Architectural->Internal->Floor Lamp, etc. These objects do not provide geometry when accessing via the Autodesk recommended geometry access method (the IExportContext). You can see the Family display of the light here...
light_source_1.png

Yet the geometry provide by Revit is clearly missing the light emitting geometry.
light_source_2.png


It seems people are trying to export the light, without the Light Source Geometry. Would it not be easy to export just the light geometry and use that?
They are using a completely different method to access the light geometry to what the plugin uses. The plugin uses the method recommended by Autodesk at https://thebuildingcoder.typepad.com/blog/2013/07/graphics-pipeline-custom-exporter.html which for me is not returning any emitter geometry.

If I have a light instance family, I use a flat geometry say 50mmx50mmx2mm (unfortunatly 2mm is thinnest you can create in Revit)
to this family, I would apply ies files and make the opacity 0
This works for me on any type of light.
Yes, this is the recommended way of adding light emitters to the scene.

Thanks

Paul