Create an HDRi environment

written by Nathan 'jesterKing' Letwory

The RenderEnvironment  represents environments in Rhino. To create an environment that uses an HDRi texture we'll be creating the RenderTexture that holds that HDRi image, and the RenderEnvironment to which we will assign that texture.

We'll be creating the RenderEnvironment using RenderContent.Create that takes a GUID, in this case the RenderEnvironment GUID which is ba51ce00-ba51-ce00-ba51-ceba51ce0000, content chooser flags that we leave at NONE and a RhinoDoc instance that we get from scriptcontext.

To create the HDR render texture we'll be using RenderContentType.NewContentFromTypeId to which we will pass Rhino.Render.ContentUuids.HDRTextureType.

<<create an HDRi environment.*>>= ./create_hdri_environment.py $
import scriptcontext as sc
import Rhino
import System

file_dialog = Rhino.UI.OpenFileDialog()
file_dialog.Filter = "EXR (*.exr)|*.exr"
if file_dialog.ShowDialog():
  <<create HDR texture>>
  <<create environment>>
  <<assign HDR to environment>>

Creating the HDR texture

As mentioned earlier we'll be directly creating the texture through RenderContentType, giving it the correct GUID.

<<create HDR texture>>= 
render_texture = Rhino.Render.RenderContentType.NewContentFromTypeId(
  Rhino.Render.ContentUuids.HDRTextureType
)

Once we have a new instance we set the filename parameter to a string that is the path to an HDRi file. To set parameters we need to bracket the call to SetParameter in a BeginChange and EndChange pair.

Additionally we'll also change the texture saturation to show how that can be done. The parameter name is rdk-texture-adjust-saturation.

<<create HDR texture>>=+ 
render_texture.BeginChange(Rhino.Render.RenderContent.ChangeContexts.Program)
render_texture.SetParameter("filename", file_dialog.FileName)
render_texture.SetParameter("rdk-texture-adjust-saturation", 0.0)
render_texture.EndChange()

Creating the environment

<<create environment>>= 
render_environment = Rhino.Render.RenderContent.Create(
  System.Guid('ba51ce00-ba51-ce00-ba51-ceba51ce0000'),
  Rhino.Render.RenderContent.ShowContentChooserFlags.NONE,
  sc.doc
  )

Assigning the texture

Assigning the texture to the environment we do using SetChild to the child with name texture.

<<assign HDR to environment>>= 
render_environment.BeginChange(Rhino.Render.RenderContent.ChangeContexts.Program)
render_environment.SetChild(render_texture, "texture")
render_environment.EndChange()

The final script

The Python-only code for this literate program can be found here.