Learn how to remove and convert scene nodes for an uninstalled renderer.
- [Instructor] With Autodesk's acquisition of Solid Angle in 2016, Arnold became the new high end production renderer in 3ds Max. And it replaced Mental Ray. And although Mental Ray is still available from Invidia as a free plug in for a single work station, there are some real key advantages to using Arnold, you may have a need to convert your old Mental Ray scenes to Arnold. Or perhaps to another renderer such as the ART Renderer from Autodesk.
And this is done using a tool called the Scene Converter and my friend George Maystree covered that briefly in the course ART Renderer 3ds Max. But I want to revisit that because we need to go a little bit deeper into the Scene Converter to find out its limitations and what we need to do to actually really completely clean our scene from all of the unknown nodes such as the Mental Ray materials and so on. So I've got a scene prepared for that and this was from another course, which is 3ds Max advanced lighting.
Go to the file menu and open and in the current project scenes open up scene_converter.max click open and the Scene Converter dialogue comes up automatically. This file contains Mental Ray legacy assets, well we want to open the Scene Converter right away, in the scene converter we have two main sections here, we have options and editor. Options are the controls for actually executing the Scene Converter scripts and the editor tab exists so that you can edit existing Scene Converter scripts or create your own.
So I'll go back to the options tab and we see in bright yellow over here some elements of the scene could not be loaded, click expand and these are all the scene elements from Mental Ray that currently cannot be loaded. Up here at the top we have the script that we are going to execute and from this file browser here, want to click on that and it takes us to our current user 3ds max Scene Converter conversion pre sets. And let's choose the Arnold preset and click open.
Once we do that over here on the right the conversion rules will change. And if we want to know exactly what's going to happen when we convert this scene we can expand all of these, and we can see all the various rules. If we wanted to execute just a single rule we could select it, and then click apply only selected. But we want to convert the entire scene so we'll unexpand this, deselect everything and click convert scene.
And now all of those rules are applied, okay. Now over here in our options tab, in the current scene status it says, inspect the scene to detect possible problems, okay well that means we need to check in on our render setup dialogue and our material editor to make sure that there's no garbage leftover. I'm going to close the Scene Converter. And go into the render setup. And very importantly the renderer section here, the pull down list, is blank. And that means that there's still a reference to Mental Ray in this scene, and as on the side the Scene Converter has an option that's supposed to change the active renderer but in my test I was not able to get that to work.
So we have to go into this render setup and manually change the renderer over to Arnold and then go to the system tab, it's important in this case to enable Legacy 3ds Max map support because my scene has lots and lots of 3ds Max Legacy maps, and while we're here I recommend disabling autodetect threads and setting the number of threads to negative one so that we'll still have one processor core available for other processes other than Arnold. Okay we've run the Scene Converter and we've manually gone into render set up and changed the renderer to Arnold.
And hopefully that means our scene is cleaned up now. So let's close the render set up and let's save this scene as a new file name. And while we're here we can see that the Scene Converter automatically made a backup of our existing scene the one with the Mental Ray assets so we could actually save over the current scene if we wanted to but I never do that, I don't recommend it, I'm going to change the filename to Scene Converter converted to Arnold.
And then click save. So we've saved that out. Now to test to see whether the Scene Converter actually worked or not we actually have to reset 3ds Max and reopen the scene because the Scene Converter has no mechanism to refresh itself, the Scene Converter only checks the scene when that file is loaded. So let's go to file reset, and click yes, go to file open recent and open up Scene Converter converted to Arnold. Once that starts to load the Scene Converter tell us that we still have some junk leftover in our scene.
So we'll open the Scene Converter again and investigate, in the current scene status expand and there are a couple of nodes that were not recognized as texture maps. Over here in our conversion rules under maps there's a rule that will convert missing text maps to quote unquote remove from scene. So this language is a little bit confusing here but what it's saying is, we're taking the source, which is the missing texture map, and we're converting it to the destination which is remove from scene.
So it worked for everything that was considered a texture map but for some reason these nodes are not registered as texture maps and therefore they didn't get deleted. So we have really no choice now but to go into the material editor and go on a search and destroy mission for these unknown notes. Okay so I'll close the Scene Converter, go into the material editor, and here are all the scene materials. We can load those all into the view in one fell swoop so we can try to find the missing notes.
There is no search engine here. So we have to kind of hunt and peck and try to find it. So let's go up to the material menu and choose get all scene materials and now all of the materials and all of their graphs are loaded in. And we'll use the middle mouse and the mouse wheel to zoom in and pan around and we're looking for anything that says missing. Okay here's one. It's a missing texture that's going, let me maximize this, we've got a missing texture, it's going to an output node to change its brightness and that's being multiplied into something else.
In a real production environment I would have to replace this with some node that Arnold can actually render. This is a missing Mental Ray node and I would need to figure out what that used to be and replace it with something new that's relevant but in this teaching example we certainly don't have time for all of that so I'm just going select that node and press delete. And I've just basically broken my shading network but that's what I had to do in order to remove that bogus node.
Okay so now we need to keep looking around here trying to find more of those, so here's another one, missing texture. And once again I'm going to delete it and once again that's actually going to break my scene, it's going to break the shader so it won't render correctly anymore at least not the version that I designed but again we don't really have any choice in this teaching example so we got to just work with what we have here. Just going to continue to navigate around in here, looking for missing textures. Here's another one, select that and delete it.
And that's all the missing textures that were on materials and we can go ahead and clear out this graph, press the Z key to zoom out to enclose all of the nodes in the graph, use control A to select everything, and then press delete on the keyboard just to clear out that view or that graph. And just to refresh your memory, the rules around the graph here are very weird if I delete a single child node like those missing textures, those actually get deleted from the scene but if I delete that entire graph as we just did, it doesn't actually delete anything from the scene, it just clears out the view here.
All right that's weird but that's what it is. Okay so we've cleared out those missing textures, hopefully. So we're going to close the material editor, save the scene, and then test it, go to file reset. Reset the scene. Go to file, open recent and reopen Scene Converter, convert it to Arnold and cross our fingers and indeed we still have more junk leftover in the scene. So we've got to go back into open Scene Converter again third time now, and what do we got here? So we can expand this and there's still one node that's leftover, hm.
Well that's odd. Okay well we'll close the Scene Converter and go back to the material editor and there's just an issue with this command. Material get all scene materials, does not actually load all of the scene materials, it loads all of the scene materials that are applied onto objects, it does not load the environment. And I've got a Mental Ray node in my environment and that's what this is here, so I had to do a lot of detective work to figure all this out, so now we're going to really, really finally clean up this scene.
I'm going to drag this env corrected over into the view, choose instance, press Z to zoom in and here's the final missing texture. And that was a Kelvin temperature node that I used to color correct the background bitmap. And if I select that and just press delete it's not really going to break my scene in this case because all I did was color correct by using this rgb multiply node, and now if I try to render this my background would show up fine it just wouldn't be color corrected.
Okay so close the material editor again, save the scene again, reset the scene again. And finally the moment of truth reopen Scene Converter convert it to Arnold.max and finally we don't get that Scene Converter dialogue. We've successfully removed all of the Mental Ray nodes through a combination of the Scene Converter and a lot of manual work. And that's how to use the Scene Converter in a complex scene in a real world production environment.
Skill Level Intermediate
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