Change texture file path

written by Nathan 'jesterKing' Letwory

Introduction

TLDR; the generated script is here.

In this script we'll retarget all image texture paths to a new path. We'll iterate over all RenderMaterials and find all the image based textures.

To actually change the file paths we need to use the SetParameter method on each texture we find.

In this script you'll see how to:

• Iterate the RenderMaterial table
• Use rhinoscriptsyntax to browse for a folder
• Use GetParameter in conjunction with System.Convert
• Use SetParameter to change values on RenderContent
• Bracket changes properly with BeginChange and EndChange

Changing the file path

We will handle all RenderContent that are image-based. Since a RenderContent, including RenderTextures can have child content we need to recurse through the entire ancestry to ensure we handle all cases.

We start by asking for the first child content of the given RenderContent. It will be an instance of some RenderContent  if there is anything, otherwise None. For each child content we handle we'll recurse, then when back we make the change and finally ask for the next sibling.

To make the change we first get the current filename of the child RenderContent. We need to use the GetParameter method to retrieve the value. There is one important issue to take note of: GetParameter returns values as objects. These implement the IConvertible interface. To get to the actual data we need to somehow convert this. A straight cast is not possible, but we can use the Convert mechanism. We know we need a string so we can use System.Convert.ToString.

For changes to stick on RenderContent in Rhino we need to bracket them between proper BeginChange and EndChange calls on the content. For BeginChange we give the Program change context, since we are changing the data through the script.

def handle_render_content(render_content, target):
    child = render_content.FirstChild
    while child:
        handle_render_content(child, target)
        if child.IsImageBased():
            child.BeginChange(Rhino.Render.RenderContent.ChangeContexts.Program)
            source_path = System.Convert.ToString(child.GetParameter("filename"))
            source_file = os.path.basename(source_path)
            child.SetParameter("filename", target + os.sep + source_file)
            child.EndChange()
        child = child.NextSibling

Iterating the render materials

To iterate over all the RenderMaterials available in our document we iterate over the RhinoDoc table called RenderMaterials:

for render_material in scriptcontext.doc.RenderMaterials:
    <<handle render content>>

Handle each render material

handle_render_content(render_material, target)

Ask the user for a target path

target = rhinoscriptsyntax.BrowseForFolder()

Binding it all together

Since we need to use GetParameter on a RenderContent it is important that we convert the data we get to the correct data type. GetParameter returns an object that implements the IConvertible interface. We can't directly cast from this object, instead we have to use the Convert mechanism. For this we import the System.Convert.

For the folder choose dialog we import rhinoscriptsyntax, and to access the RenderMaterial table of the document we import scriptcontext.

import os
import rhinoscriptsyntax
import scriptcontext
import Rhino.Render
import System.Convert

<<method to handle render content>>
<<ask for target path>>
<<iterate over all rendermaterials>>

And that's that.