Rendering with Thea (was: Iray plugin)

I just downloaded the Iray evaluation for rhino and was wondering if anyone has been using it? I am currently trying to find a new render option without breaking the bank.

What is the learning curve like for Iray?

I will be using it for architectural rendering, BTW.


I tried it during the beta and wasn’t all that impressed. The material system was really weirdly implemented and since it’s originally a node based system they did a strange conversion of that into relatively static materials with layers and only parts of the options exposed. And the materials didn’t show up in Rhinos Material palette but in their own window.
I also found it on the slow side.
Overall, I didn’t follow up on it further after beta since it didn’t convince me, so it may be different in the meantime.

I personally use Thea Studio.




Thanks for the response. I played with it for a bit yesterday wasn’t very happy with it. You’re right, the material palette was very annoying. I like that they tried to simplify some things but they over simplified in places.

I guess there is a trend towards these RT renders in a viewport that I am still adjusting to. They are really taxing on my current laptop. What do you like about Thea?

Well, a good renderer should use 100% of your CPU and 100% of your GPU to be as fast as possible - being “taxing” is what you want … :wink:
If your laptop can’t handle that, it’s not the renderers fault…

And you do not have to render in the viewport (at least with Thea) if you do not want to, it comes with a separate “Darkroom” window that you can move to a separate monitor (that’s what I do).

Simplifying the way Iray does it may be good the first couple of days or weeks until you know the tool, after that it’s mostly in the way.

Thea does use CPU and GPU at the same time (if you have a Nvidia GPU that is (for now)), has a rather clear material system that is the best one I know of the non-node-based-renderers out there and is well integrated in Rhino. They constantly improve the tool, there is a good community and they also constantly extend the material library with high quality content.
I bought it in 2011 and didn’t have to pay for an update yet.

But take this with a grain of salt - I do CG for about 20 years.
YMMV :wink:



The problem I am having as far as over taxing the CPU is because my CPU overclocks to crazy levels and trying to change it on windows 8.1 has proved difficult. I am taking it into the shop on Monday to get it fixed once and for all.

I know it’s not the renders fault, it was me just venting my frustration. Currently I have to render on an old laptop with Windows 7.

I’ll check out Thea and see what it’s all about.


I see.

As for your initial question: learning curves are very different, depending on former knowledge and general learning approach.
I usually learn a new renderer in a day for the basics, another for the more specific stuff and then it may take a long time to get into the real nitty-gritty where you know all the ins and outs, the things that don’t work in specific situations or need some obscure function enabled somewhere etc.

iRay didn’t take me long to learn the basics, but I found the material stuff very annoying, so I didn’t go into it’s depths. In theory there are some tools that let you create your own shader networks for it (was it .mlt files?) but they are not part of the package and somehow that felt rather unconnected to me - I want to set up my materials right inside the renderer, not in an external app (at least not at the shader level, textures are a different thing).

I recently bought Houdini and learned the included Mantra and the 3rd-party renderers Redshift and Octane in about a week, good enough to use them in not too advanced situations.
But like I said, I do this for 20 years as my main job.
So it depends mostly on your former exposure to other renderers and your overall understanding of the underlying principles.



I can usually get the hang of rendering software pretty quickly. I’ve been using vray for rhino but it is an ancient version for Rhino 4 and V-ray can be a bit of a hassle even though the quality is good. I just updated to Rhino 5 about a year ago so that shows you how far behind the curve I am on the latest and greatest. But modeling a something in Rhino5 and then saving it as a rhino 4 file so I can render is it just a hassle of the highest order.

I am really leaning towards buying Thea. I like what I have seen so far and I really want a renderer that uses the GPU.
I need to start pumping out some renderings ASAP so I am leaning towards pulling the trigger on Thea.

Do you know if I would need two licenses if I wanted to use it on two machines?
Any other thoughts before I try Thea out for real?

Thanks a lot for your help. Oh and I finally fixed CPU overclocking problem so that is a relief

Okay, so in that case I think what may need some getting used to is unbiased, physically correct rendering.
Vray, Mental Ray etc. were basically “faking” stuff in the past. In reality there is no such things as specular, reflection, diffuse etc. as separate entities - it’s all reflection. In the olden times, those things were invented to make rendering faster and (in the case of specular) make invisible lights visible and stuff like that.
In reality, all lightsources are visible objects and have a certain size, which defines how smooth their shadows will be.
And all surfaces either reflect the incoming light or let it through, so you only have reflection and transmittance, but a smooth surface will show sharp reflections and a rough one will show diffuse reflections.
And this is the core of unbiased, physically correct rendering - it works much more like reality.
So I personally find it much easier in the end, but after using the old-style stuff for so long, I needed a while to re-adjust.

Thea is not a hardcore-unbiased renderer like some others, so you at least have a diffuse setting in the basic shader (which is a bit of an allround shader), but there is no specular, only reflectance, and your surface roughness decides if it’s sharp or soft.
The glossy shader on the other hand does not have diffuse and is specifically meant for metals and transparent material like glass and water.
SSS is for Subsurface Scattering (relatively expensive to render - for most things the basic shaders “Translucent” setting will do).
Then you have ThinFilm for things like windows - it’s basically a glass shader for thin sheets of glass (single polygon) where refraction does not play much of a role - and it’s much faster to render than real glass. It also allows you to do soap-bubble like effects including the colouration based on physical reality.
And finally there is a coating shader, that you can put on top of for instance a wood material done with the basic shader and it gives you that typical coated look.

You combine them in layers (like a coated SSS or metal or mixtures via textures) and can also have things emit light, use displacement, clipping (for things like the alpha-channel of tree-leaves for instance), things can contain a medium (think visible light rays, but can be used for semi transparency etc. too).

There are also other areas where the physical realness hits you: You can’t for instance change the brightness of the sun. What you do instead is increase or decrease the ISO value of your display settings - if you’re doing photography, it should be rather logical actually.

And lights should usually be objects that emit light, with the least amount of polygons possible (for speed) and not touching or too close to other objects (against fireflies and long rendertimes). But there are several tutorials available on the Thea forum that should get you up and running rather quickly.

What you get out of it is: stuff looks real right away.
I got tired to try getting a phong shader look like anything real in the olden Mental Ray :wink:

I use “Presto MC” for pretty much all my normal work (using GPU and CPUs) but Thea has several rendercores, some biased, some not. TR1 and TR2 are much slower, only use the CPU but can render crazy complex lightpaths, caustics, multilayer materials etc. - for some pictures I rather render overnight and have all those bells and whistles.
I actually do not use the biased modes.

Try the demo with some of your own projects and see how it works for you.
I use it on a 6core i7 @ 4.1 Ghz, a GTX 660 TI and a GTX 980 TI and it flies.
On my laptop with a GeForce 840M with 2 GB RAM it also works fine, although slower of course.

Hope this helps :wink:



You can install Thea for instance on your main machine and your laptop no problem.
You can’t use them in GUI mode at the same time though, but you get two network render nodes with the license and setting it up is the easiest I’ve ever seen, so you can render on 3 machine with the initial licenses you get.
Additional network render nodes are something like 49.- Euro I think.

If you want to work with Thea in Rhino on two machines at the same time, you need two licenses (same as with Rhino and many other tools too).



Oh, and to make that more clear: unbiased mainly refers to not having a fixed number of rays being sent out. So you do not define your render settings before you render and if it still is grainy, render again from scratch with increased rays like in biased engines, but instead you simply let the image render until it’s looking good. In Thea Studio, you even can stop renders and continue later.



Thanks for the all the info. I will have to do some digesting on your post and will check out all of the available online stuff.

I am not a CG artist but a designer, architecture and furniture design mainly, so I am not very well acquainted with the nitty gritty of rendering programs. A lot of the terminology you mentioned in your post is outside my wheel house. But that is mainly because I haven’t found a rendering engine that I wanted to invest a lot of time into. With V-ray I was lucky that I found some settings online that worked well for my needs and I would tweak a bit until I got a decent result.

I just want solid renderings with materials, good shadows, and some depth and then I take it into Photoshop as soon as possible. And simple clay renderings that I can use for diagrams, concept images, and renderings where I am not really looking for something realistic. I don’t render trees or that sort of thing but add them in Photoshop. So I think that the results that I would be satisfied with might not be up to par for you.

I just spent some time downloading some materials from the Thea website. I like that they have a lot of nice brick materials. One type of material that I am always looking for is wood siding. I use it a lot in my designs. There was a painted plank material on the website but that is it. Do you know of any other places I can find wooding siding materials for Thea? I can always create them but I was hoping for a few options out of the box.

One more thing and I will stop bothering you(at least, for the time being). I don’t like super complex or heavy materials. They take for ever to render and give me more than I really need. I can do things in photoshop quickly to add any needed depth if a material came out a bit flat. A little bump mapping and I am cool. So what is a good method for paring down the high resolution materials that I am getting from the website so that I can decrease my render times?

Thank you so much for your help.

Sorry one more thing, easy answer I am sure.

How do I import material libraries so that they are in the material browser? I am sure there is a good way to keep the materials organized but just interested in how you have it setup.

  • You can set a global switch for Thea to do a fast clay rendering (Thea Render panel in Rhino -> Rendering -> Clay Render).

  • Presto AO isn’t photorealistic, but even faster than Presto MC (Presto is the name of the GPU&CPU renderer in Thea). I never use it but it may work for you.

  • You don’t have to tweak any settings normally in Thea Presto and TR1/2. In some cases with lots of transparent objects, you may have to increase the ray depth (or even better use the extended tracing option) - TR1&2 use unlimited raydepth anyway.
    That is another plus of the unbiased physical correct engines. :wink:
    I wasted way too much time in my life to tweak render settings…

  • I never use wood siding so I’m the wrong person to ask. :wink:
    But wood is the one area where the factory materials are a bit short. You may want to ask this in the forum, but be aware that some areas are only accessible for Thea users - try this link:
    But doing your own is also very simple - usually you take a basic shader and put the texture in the diffuse and bump channel, then add a coating shader on top for lacquered wood and adjust roughness to taste, depending on how shiny you want it.

  • Thea doesn’t care much about how complex objects are or how large the textures - compared to other renderers it feels like magic. I never bother scaling them down. But if you do, I personally would scale them down in Photoshop and save them as .png, not jpg. I know that many people don’t care much, but .jpg is lossy and especially in normal maps that can create ghosts. In memory those textures are expanded to full uncompressed RGB anyway, so you only save HD-space, not memory.
    What you can do is save greyscale images, that actually should save memory (for bumps - although I often use the same image for diffuse and bump, which needs even less memory since it’s the same image).
    But try out first if it really makes a difference in Thea.
    It is not Vray.

As for the library:
If you install Thea, it asks you for a library location. I have mine on an additional, larger HD. In there you have all the materials, colour palettes, textures, ior-files etc. So all the factory materials go in there.
Since I like to keep things organised, I do not have my own stuff in there, but in a separate folder somewhere else. Inside Thea Studio and the full Thea Material Editor in Rhino (which is what I prefer to use) you can create as many tabs in the library as you want and link to any location, so I set up additional tabs for stuff I downloaded from the web or the forum and one for my own materials (also to not confuse copyright issues).
The official libraries you can download for instance with the Thea Render -> Update app or through the forum come with installers and install in the same path that you set on installation. The downloads from the material library are rather mixed in that regard, since every author decides where he puts his stuff. I don’t like that, so I either install them manually to a place of my own choosing or install them and later move them to the place I want.

These are the official Thea factory libraries:
I recommend them all. :slight_smile:

And these are the same as single downloads mixed with user contributions:
The user materials are of mixed value - some are great, some I personally wouldn’t use.

Oh, one more thing: The Thea for Rhino Videos may still show an older interface. The very latest version of T4R had a rather drastic change in that regard and I’m not sure if they updated the videos already - some other users here got confused…



I’ve been playing around and I am really liking it so far. I can get easy previews to check lighting and texture mapping that look good and are fast. Using the GPU with the CPU makes all the difference.

I ran across a great site that has a lot of good info for me and also a ton of materials that you may want to take a look at

He’s got a lot of wood on there so I was happy to find it.

Thank you for all the help


Cool, feel free to ask if you get stuck.

And yeah, that guy and his website are great.

And the Thea Forum is also highly recommended, it has many PDF tutorials on optimisation and the do’s and don’t’s and how to improve the look and speed of things. The community is normally quite helpful and friendly.

I hope it works well for you - I used pretty much every renderer on the market and like Thea the most for realistic work. With a good machine, you can get extremely fast and good results.



Well after playing with the demo all day yesterday I’ve ended up purchasing Thea. Bought it from a Novedge so they have to send my purchase to Thea who will send me a download link. Anxiously waiting. It took me a while to get a grip on the Matlab but it is becoming more clear.

Have a few questions while I am waiting:

  1. I use a lot of blocks and in most cases there are nested blocks in those blocks. So I have to apply materials to the entire layer. This is fine for simple materials but if I have a tile material for a wall getting the texture mapping correct is a pain. As far as I can see the only way to adjust the texture mapping in this case is in the matlab. So I have to preview render the block to see the mapping. Then open matlab to adjust and then close it and then preview again.

Is there a way to adjust mapping for a material without using the matlab?

  1. I also noticed that when I am using either the interactive viewport and the darkroom to preview I am still maxing out my CPU even with PrestoMC enabled. It seems like my GPU isn’t helping much in the render process. Is there some adjustment to the settings I can make to help with this? My card is compatible with the Thea. I just would like m quick preview renders to not max my CPU.

  2. I haven’t found a whole lot of helpful info on the Thea forums. In the Thea for Rhino section there are only two posts that don’t even have replies. It seems that info and more detailed tutorials on the plug-in are a bit scant. I haven’t started fooling with taking scenes into the Thea standalone yet and it seems that most of the tutorials and information are geared toward that.

Thanks as usual


1 Like

Hey jeff,

1.) Yeah, texture scaling is not yet available directly in Rhino. I usually UV map my objects in Rhino, much easier and more direct.
So if your Thea materials are set to UV (which is the default for new materials), you can directly adjust the placement for instance with a cubic projection. I mostly prefer that over using Theas cubic projection since I can adjust the placement more detailed per surface this way.
But post it in the T4R forum as a REQ, it would make sense to have it right there in Rhino now that they integrated so much of the GUI already.

I only use blocks for smaller stuff that repeats often, so probably don’t run into that topic as much.
I find the block implementation in Rhino a bit annoying actually.

2.) In the Thea Render Panel in Rhino, you can go to Rendering -> Devices and select what devices on your machine should be used at what priority.
Your CPU will still be maxed even if you set it to the lowest settings if nothing else is going on on your machine, so you may have to turn it off completely.
Honestly, this is the first time I heard that somebody does not want the rendering to go as fast as possible :slight_smile:

My i7 6core @ 4.1 GHz contributes quite a lot, the lower spec i7 quad on my Laptop too.
And I want them to be maxed, that’s what they are there for :slight_smile:

Why does it bother you? Is your cooler dusty?

3.) The Thea for Rhino forums aren’t very active yet but it has a lot more posts than two - you may have to change the forum settings at the bottom to show you all topics.
What I was refering to was mostly the general areas though, the program specific areas are more for plugin feedback and support, less for general Thea questions.
It think it makes sense to understand the standalone as well, since it’s the thing behind the plugin and all it’s concepts translate to the plugin, sometimes I even export to Studio for some features that Rhino does not support directly or to concentrate on rendering and material 100%.
If you mass-create materials, it may also be faster to do in Studio, since there you can for instance scale all textures at once, a feature dearly missing from the plugin so far (I requested it recently).

BTW: Thea supports all the Rhino render effects, I especially use the edge rounding a lot.Displacement is better handled by Thea itself though.




Maxing the CPU was mainly a problem before I adjusted the CPU usage settings. I have an i7 quad core @ 2.80 GHz and whenever I rendered it would overclock to 3.8 or 3.9. It sounded like my computer was about to explode. I also took my laptop to the shop this morning got it tuned up so it is running way better now.

Still waiting for my Thea license. Itching to actually create some renderings. Gonna delve into TheaStudio in the meantime.

Do you usually do your final rendering in the darkroom or do you take it Studio?

A question about material editing. I have a wood siding material that I really like but I need to adjust the color of it. It looks like redwood and I am going for something closer to cedar. I have been tweaking the texture in photoshop and then making it a material in Thea but it still isn’t quite right once I do a test render. Needless to say, it is a pain to be constantly tweaking in photoshop. Going back and forth between programs is such a hassle. I imagine that the matlab has the tools to allow me to do the tweaking but I am still getting a grasp on all of the features in the matlab. I think the matlab is clearly the most complex part of Thea. I still am confused on the best way to utilize the texture editor in material creation.

So if the main thing I am looking to do is tweak the color of a material which sort of adjustments should I try in matlab?

Thanks again


Hey Jeff,

normally it should only go to such high clock speeds if only one core is running - that’s a feature of the i7, but on a laptop it may be problematic. I have a huge cooler on my stationary CPU with two 12cm fans - silent and perfectly cool no matter what I do.
My laptop goes a bit louder and hotter when I render full on with Thea, but all within the “I’m working” realm, nothing close to exploding.

Normal renders I do in Darkroom directly. For quick previews I often don’t even bother with production mode, just let it cook until it looks good and then save the image out (you can save while rendering and sometimes even have to since they still didn’t implement the zoom in Darkroom, so for large images you can’t really tell if there is noise left and how much).
But usually I use the production mode Presto MC in Darkroom, since it offers masks, alpha channels and all the other stuff the interactive mode does not have.
The cases where I render in Studio are usually the ones where I do really huge or taxing images and only want Thea to be running, not Rhino on top. It’s a tiny bit faster and I can zoom into the picture while rendering etc.
And as I said before, sometimes I like to just concentrate on the rendering and don’t change the scene anymore, then I like to use Studio.

As for tweaking colours: For small casual tweaks I do it in the Texture Lab in the full Thea Editor.
You can drag your texture from the material slot it resides in to the preview area (I have the previews at max size at all times to really see stuff). There you have Options like the mapping, repetition, Coordinates like size (in different spaces), rotation and finally the Tone where you can do colour adjustments.
Sadly it does not offer a hue setting, but you can adjust the individual R, G and B components, saturation, brightness, contrast etc. (±100 is the range). You can also clamp and invert the image here.
What you also can do - but this isn’t my favourite thing in Thea - is using the grid. Put for instance a colour into the grid cell next to your wood and make it the colour you want for your wood. This get’s multiplied so white is neutral and a full colour will do complete colouring while a grey tone will just darken it.
If you put stuff in different rows of the grid, you can blend between them.
I’d prefer a full photoshop like layer structure with more modes, but for the time being this is what we got.

When you like the result, you can drag the big preview on top back to the material slot you want it in.

Generally you can drag and drop between slots and also copy and paste slots (right mouse menu).

If you only want to change small stuff and don’t need the grid, you can also click on the texture slot in the material itself to have access to the basic texture settings.



Oh and one non-obvious trick I found helpful:
You may notice in my screenshot that I have Layer, Scattering and Structure open at the same time - this can be done by holding CTRL and clicking on those three icons. From then on Thea remembers to open them together (which is what I always want).