Rendering with Thea (was: Iray plugin)

I can’t seem to change the color correctly.

When I use tone mapping on the texture if I adjust the Red value it makes it red. But then if I change another color it just becomes a solid color. I am going to try and delve into the tutorials now that I have my license

Huh - can you post a screenshot? I tried it here and it works as expected.
It goes from -100 to 100 as I wrote above…




Sorry for the long reply. I have been out of the country for a while. I’ll send you a some screen shots when I get a chance. I was finally able to get the right look of the material using Photoshop but for further reference I would like to be able to do a lot of my material and texture adjustments in Thea.

Just didn’t want you to think I just dropped off the map. You have been super helpful and want to keep this thread going. I wish we could change the name of the thread because aside from the first few posts, it has nothing to do with Iray. This thread could be useful for people who are looking for information on Thea.


No problem :wink:
As I said, I’d wish there was a hue value instead of just the RGBs and more layers modes in the Grid, so for more complex or subtle changes, Photoshop may not be the worst idea :wink:

You as the thread starter should actually be able to change the thread topic. I checked one of my own topics and there was an edit icon next to the headline. Otherwise ask one of the admins for help in a PM.



Yes, a simple hue button would be great.

So I have finally gotten around to actually doing some test renderings and taking it from the dark room to the stand alone. I am still struggling with a few things though.

  1. is finding a simple environment set up that I can use for daytime scenes. I don’t necessarily need a crazy hi def HDL environment just something simple. I like to do a decent amount of the work in photoshop so I am really just looking for a simple exterior setup to get me something for photoshop. Any tips on this? I don’t know the type of renderings that you do but if you have some kind input or experience with it let me know. Trying different environments I either end up with something too washed out and bright or too dark, even after I tweak shutter speed ISO etc.

  2. And I’ve always had trouble in rhino doing renderings where the camera is at normal eye level. The problem is getting vertical lines to actually be vertical instead of skewed a bit. I’ve tried adjusting the lens length but I can’t find a fix for this. Any idea of what I can do?


1.) I almost always use HDR environments and collected a lot of images over the years. Thea automatically deals with them no matter what resolution, so you do not need to bother with different sizes in the different Thea Environment/IBL slots. You can set the brightness and angle for the HDRI right there, which I often do.
I also created versions of my most used HDRIs that are black and white (Photoshop -> Channel Mixer -> Monochrome does a good job of it, better than reducing saturation), since often I do not want the colouring from those images.
There are also many studio-like HDRIs available on the web and some I created myself.
The Thea Sun I also use regularly, the sky not so often, since most of the time the colour is not to my taste - sadly it can’t be influenced much.
You can find many links to good HDRIs in the Thea Forum.
Some come with Thea if you download all the extensions or look in the resources Forum.
I created drag-and-drop ready environments from those I use most often in Thea Studio, in Rhino you can import and export Environments via the Thea Render menu on top.

If the HDRI has to be very bright for lighting but not for background, you can either use one of the IBL sets where there is both a HDRI with less resolution for the light and a very detailed JPG or PNG for the background, or use the same HDRI in both slots but make the Background one you see in camera darker.

2.) For that you use the Thea Camera Shift (I assume you have the Thea Panel in your panel area open on the left). Make sure your camera is totally straight horizontally and on the level where you want it. Then you go to Thea Render panel, Camera -> Lens -> Shift Y and adjust the value while having either interactive darkroom or viewport rendering running and adjust your view to taste. This will prevent falling lines, but the camera has to be straight.
Sadly the Rhino camera does not have shift, so the viewport doesn’t show it correctly… :frowning:

I hope this helps,



I finally got a good environment and was able to tweak the camera and it is looking good.

Going to work on the shift next. Do you know a good way to straighten the camera? I am assuming straighten means the camera is looking straight ahead rather than looking up or down.

One thing I am having trouble with and I don’t know if you have any experience with it but it has to do with texture mapping on a certain element in a block. I have a block which contains a staircase and an elevator (all exterior elements). The different elements are on their own layer so it easy to apply the material to different elements in the block. However, because I can’t select a particular element and change its texture mapping I am forced to use the matlab to adjust scale, etc. However, this has proved really challenging. I am trying to add a wood siding material to the walls of the elevator so I really need to use box mapping. I may just have to go to the blocks and remove the walls from the block and then copy them into the model as regular surfaces but it would be nice to find another way.


Wow! Thanks for the shift Y tip @Thomas_Helzle ! Works perfectly. This is going to be super helpful

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Great it worked out.

As for the camera: Hit F6 in the viewport with the camera you want to work with, that makes it visible.
You can now select the points of the camera in the viewport and move them.
[Rant mode on] Rhinos camera is probably the worst in the known universe, at least if you come from “normal” 3D software where cameras are real objects and can be normally moved, selected and rotated etc. [Rant mode off]
Alternatively you select the respective viewport and then look at the object panel on the right side, there you can see both the coordinates of the camera as well as the location of the target it’s looking at (I don’t think you can get rid of the target). If both are on the same height, you are looking straight forward and Shift Y should work.
(This “Shift-thing” comes from real architectural cameras with tilt-shift lenses).

As for blocks: If you UV map the parts in your block correctly, you then shouldn’t have much trouble with the textures. So if you need cubic mapping, it may be fastest to apply that in Rhinos object properties, since then you can scale it directly there - if your blocks are external, in a second instance of Rhino running in parallel (that’s what I do).
Blocks in Rhino are very unflexible in their design and editing them is a pain, that Theas texture scales aren’t available directly in Rhino doesn’t help, but for me it’s more a flaw in Rhinos blocks than in Thea (a moot point in the end of course… :wink: ).

Thea can also use multiple UV maps if you need different mappings on the same object.



Can I perhaps also ask a question, @Thomas_Helzle?

I have built this simple scene to play with lighting in Thea.

Now there is quite a few things that can be done: Light portals, Presto MC, Presto AO, change the window’s geometry (it has two 8 mm polysurfaces…), Extended Tracing, Tracing Depth, AO, invisible lights inside the room, Thin Film. Can you perhaps give some advice on what you would do to get fast, beautiful light without noise here? Milgard.3dm (5.5 MB)

And is there perhaps something like this (V-Ray) in Thea to show overexposed areas??

That’s an extensive topic and has many answers:

  • If your main concern is fast and noise free and you can live with some loss of detail, go with biased rendering (Adaptive BSD) - that works basically like Vray or other such renderers (similar to global gathering).You then have to set all the additional settings and parameters though. I honestly never use it, but many swear on it.
  • If you want fast and unbiased and no fiddling with all the biased parameters, I would go with Presto MC, since its much higher quality (I never use Presto AO myself, but if you don’t need things fully photoreal, it may work for you).
  • For the windows, you always want to use single-polys there - having glass with real thickness and refraction only adds something if you do a macro shot of the frame and have to see it fully, in all other cases it adds huge amounts of useless rendertime for pretty much zero gain, since thin panes of flat glass do not show any interesting behaviour from the refraction.
  • Second part to this is not using a “real” glass material, but a thin film glass (see the factory material library -> Transparent -> Thin Glas Clear. This renders very fast, does look for all intent and purpose like glass but without the render overhead.
  • If you light the scene with a HDRI, yes, you definitely should use light portals in the windows to show the renderer where the light comes from - otherwise it will search too many directions for nothing.
  • Extended tracing is not very important in the case of your scene, since there is only one window pane to go through. But if you had a table in the room with reflecting and/or refracting objects like bottles or glasses, then it can be very good to enable extended tracing. What it does is, that it only uses the normal tracing depth for all diffuse surfaces like walls etc. but for reflecting and especially refracting surfaces it uses the extended depth you set - this prevents you from having to set very high tracing depths for the whole scene when only the bunch of bottles on the table would need it.
  • Other things like if you want invisible lights inside etc. really depend on the shot, there is no general rule. In the end it boils down to: Whatever looks good and makes the customer happy. Photos of indoor architecture are very often not completely “pure” either, since the contrasts between inside and out are very extreme for cameras. So you often see additional lights used, postprocessing or multiple exposures taken so that the outside does not look blown out.
    The good and the bad side of unbiased, physically correct rendering is, that you inherit all the good and the bad stuff from reality too :wink:

And from there, it’s simply down to renderpower and time…

Thea has the photometric analysis in the darkroom, but that’s more for architectural use to see light distribution, less for imagery. Thea also does not have a highlight compression feature. I usually do that in Lightroom from a 32 Bit floating point image that can hold higher-than-1-values (a HDRI format like EXR for instance).
Would make for a nice feature request though :wink:
You can also work the other way around, keep things darker, save as 32 Bit and then adjust in LR or PS.



P.S. @jtreitz: Changing the topic title would really make sense now. See if you can edit it, otherwise ask one of the mods. Maybe at one point we can even get a Thea subforum going if there are enough users. :slight_smile:

In general I am more or less just interested in lighting rooms and lighting situations like these are most interesting for me: 1, 2

As far as the biased unbiased thing is concerned I am not able to have a real opinion. I liked V-Ray’s results and in one of the PDFs for Thea it says:

There exists an old “trick” which is to use a high gamma value and then add contrast and saturation to it. Some render engines do this by default as they are more focused on making renders that looks closer to how our eyes see reality. This of cause alters the way light flows inside the scene and is no longer physically correct.

I understand: photoreal is not what you see in reality anyway. To me it is just important that things look somewhat beautiful. (The lighting for the images on the two sites above looks very good to me…)

I had found this out, but still when I use Thin Film glass the light loses energy on its way through it?! Even when just using a single surface?!

No, there are double-glazed windows in the example and I already used Extended Tracing. But I just turned it on and played with values without exactly knowing what I am just doing… My results are good, but pretty slow.

I guess that is the real reason why I need a nice GTX card. When being patient my CPU is perhaps fast enough for a final rendering, but it’s not enough for having a good time while experimenting…

So, when something looks (just slightly) overexposed I still have all the data I need to get a proper image in PS/LR?


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What engine is the best for you in the end I can’t say. I personally don’t like Vray and it’s look much, but that’s mostly a matter of taste or preference.

  • Thea is photorealistic and physically accurate, so if something reflects light (like the thin film material), not all the light goes through the material as well. This is how reality works. :wink:

  • You can disable shadow casting in the Thea object settings for the glass, normally that’s not important.

  • Don’t use an infinite groundplane if you don’t need it and don’t see it.

  • While you can limit yourself to CPU, the real power (especially with the Presto engine) lies in GPU rendering. I use a GTX 660 TI for my two monitors and a GTX 980 TI purely for rendering. If you don’t use any good GPUs, unbiased rendering is not ideal and it may be better to dive into Adaptive BSD (can’t help there, don’t use it myself).
    Indoor scenes are always tricky and harder/more time consuming than open spaces, that’s just how it is.
    Many people use one to four Titan X cards for that reason…
    Or network rendering which works great with Thea.

  • Yep, 32 bit floating point formats (like exr and hdr) can hold values outside the 0-1 range while integer based formats clip them (most 8 and 16 Bit formats like bmp, tga, png).
    That’s also why you use HDRI images for lighting - the sun in such images can have a value like 5000. while white paper may only be 0.97.



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Awesome - thanks! :slight_smile:

Thanks, Tom, I found some threads about Presto AO on Thea’s forum and am testing all the settings now… And guess I am getting a proper card, too.

Sounds like a good plan to me :wink:

I was very sceptical regarding GPU rendering for a very long time, since cards back in the day didn’t have enough RAM to make it really work and there were not many options in software. But nowadays there are solutions for everything. Cards with lots of RAM, out-of-core rendering for instance in Redshift (hopefully Thea will have that too in the future), bucket rendering in Thea so not the whole image needs to reside in RAM (important for large scale renderings) and the CUDA and OpenCL specifications have matured a lot as well.
Now I can do product shots in full HD in about 2 minutes on my average machine with Presto MC that look good enough for communication with the client, the final I may let cook 5-10 minutes. Some years ago that would have been 10 to 100 times as much at that level of quality (I used to render such images overnight with Thea TR1 or TR2 and still do sometimes if I need perfect results for complicated scenes).

Today I would rather buy a new graphics card than a new computer. CPU development has slowed down a lot.
My current motherboard can only hold two GPUs, but my next one will definitely have four slots.

The GTX 980 TI is still great, but if you can afford it, I’d look at the Titans or the 1080.

Here is an overview of results with the Thea benchmark tool beta that may be helpful:
Note that the 10xx cards aren’t officially fully supported yet, although there is a temporary solution already, but they may not yet perform as well as they will.



[quote=“Thomas_Helzle, post:37, topic:36663”]
The GTX 980 TI is still great, but if you can afford it, I’d look at the Titans or the 1080 … Note that the 10xx cards aren’t officially fully supported yet, although there is a temporary solution already, but they may not yet perform as well as they will.[/quote]

I am probably going to get a cheap GTX 670 now and add a 10x0 later. Getting a 10x0 now makes me wait for the Thea people. And I am already annoying often enough. :disappointed:

[quote=“Thomas_Helzle, post:37, topic:36663”]
I was very sceptical regarding GPU rendering … Today I would rather buy a new graphics card than a new computer … CPU development has slowed down a lot … My current motherboard can only hold two GPUs, but my next one will definitely have four slots.[/quote]

GPU rendering is much older than my first renderings, so I am not really sceptical. Still, right now it’s more about skills for me…

Yeah, I have a lower spec card for the monitors too, so that setup can make sense. I set it to low priority so I can still navigate the OS without stuttering - just don’t expect any wonders from the 670… :wink:



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back again.

I’ve run into this problem that I feel should be easy to solve but I can’t get it to work. it has to do with adding custom folders to the material browser. I was able to add one of my folders to the browser successfully a while back. This gave me access to two folders in that folder which were full of materials. However, I have added other folders into that original folder but I can’t access them through the browser.

As you can see, the two other folders are visible but i can’t select them and get inside the folder to select materials.

What am I doing wrong here?