Thea tricks: good and bad practices

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quickit
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In order to save the hassle of searching the forum to find good practice tricks , I'd like to post here all the findings in one thread, possibly sorted by thematics. I'll try to keep it clean, even if I'm not a modo... :D
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NOISE
  • For example, I'd like to see a tutorial addressing all the noise debugging issues in Thea presto.
    Basically, what is responsible of the noise and how to fix it, or to lessen it. Here are my empirical observations:

    For interiors with sunlight:
    Often the interiors shots are doomed with lots of noise, due to the complex nature of ray paths (sun rays must pass thru glass, direct lights, indirect lights, global illumination, etc.)
    - If possible (if the glazing is not visible, or if no reflection is to be seen), get rid of the facade glass panel itself, just keep the frames (keep the glass mesh in a hidden layer for shots where it must be visible);
    - If not possible (if the glass reflection play an important role in your image), use singlefaced glass (the famous thin glass shader) everywhere possible (and keep thick glass where it matters - where you need refractions like in bottles for example).

    use thea materials
    - What I mean is: avoid leaving sketchup materials in the model if possible.
    - white SU materials (like white 255) are the worst: they tend to produce noise easily.

    Avoid geometry active emitters and use omni/IES/spotlights instead
    - is the simplest way to keep noise away but it's not always feasible

    Mesh light (emissive material on meshes) :
    - simplify geometry, avoid high poly (simple planes or even triangles work best)
    - I tend to give reflectors and 3d lightbulbs a passive self-illum shader and add an IES light instead.
    - always keep the emitter (omni/IES/spotlight) away from the geometry.
    - Mesh light vs Spotlights: "The polygon emitters are easier to find by the progressive modes AMC/TR1/TR2/Presto, because they have a size. As long as the polygons are simple, they will render faster. All light sources are pointlights, which means that the light comes from a single point. AdaptiveBSD deals with pointlights more efficiently." (Tomasz)

    IES light
    - some ies produce more noise than others. Check my other https://thearender.com/forum/viewtopic.php?f=82&t=19588.
    My recommended best of are 7, 10, 12, 13, 16, 19

    Overexposure
    - in Thea, the noise doesn't seem related to exposure so it's better to underexpose the scene to protect hilights clipping (even more critical if using default clamp level 1.00),and correct the exposure back in photoshop.

    HDRI
    - big HDRI files (150Mb+ files) tend to generate more noise. As a result, it's recommended to keep the lighting HDRI low resolution (but still high dynamic) and keep the hires HDRI for the background/reflection slot.
    - using very small values of intensity (0.01) seem to generate more noise than values close to 1.00
    - therefore it's good practice to keep the HDRI intensity between 0.1 and 1.0 and play with the physical camera exposure to get the correct exposure.
    - Fireflies/Hot pixels: some HDRI tend to produce very bright spots because of a too bright sun. To get rid of them, dim the sun in a HDR-editing software.

    DENOISER
    - this feature is very high in the wishlist since rev 1413 (noisier Presto MC);
    - third party denoiser solutions for Photoshop: ArionFX, Topaz Denoise, NeatImage, NoiseNinja, PhotoNinja, Nik Dfine, Noiseware
    - interesting read: https://fstoppers.com/originals/ultimat ... phy-122259
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ASSETS
  • Textures
    - black material instead of the beautiful shader you spent hours creating? the texture is lost.
    - it means a) you're working on another computer and need to reinstall the materials on the new computer, or b) the texture map path has been changed or has been deleted (you can open the Thea Browser and use the external dependencies to check and fix the paths)
    - Keeping the texture next to the model will always work, in the same hierarchical folder. Of course, doing this will use more hard disk estate as basically I'm encouraging duplication of assets.;-)
    - You can use right click on Model Info in the Thea Browser to gather all the assets at once, and create an archive (zip pack) file containing the skp and the assets. Very handy when sharing a project.
    - Careful though as sometimes black materials remain, when they are "hidden" in Thea proxies. In that cas, you need to fix the texture paths directly from Thea Studio by opening the corrupted Thea Proxy and checking the texture path in the Mat Lab.
    - Network folder: try to avoid moving/renaming the textures/folders because there is a risk that a model uses the path.

    Naming habits
    - Always use lower cases: Thea handles upper cases and lower cases separately so Titanium will always be alphabetically sorted BEFORE aluminium. if you don't want to waste time looking for models/materials because of bad sorting, take the habit of lowercase naming. Of course, I can imagine there are cases where you'd want to use this Thea particular behaviour to separate Aluminium from aluminium (Aluminium being a generic shader and aluminium a texture for example)...

    - avoid the use of accents, like in "Arañado" or "strié": they aren't recognized by the ressource collector (when you save skp with dependencies).

    - Network folders aren't correctly alphabetically sorted in the Thea Browser of Thea4SU but this is a bug.

    File Heavylifting anyone?
    - Not strictly related to Thea but I noticed that the use of the adequate file format lead to faster saving/loading times which is always welcome.
    - perhaps a too heavy HDRI? or too big texture files? It depends on the cases of course, but using 4k tiles is usually overkill and the use of JPG files instead of BMP, TGA or PNG can reduce considerably the file load. Keep an eye on possible improvements in texture sizes (lesser is sometimes better) or file formats (do I loss so much if I replace the 50Mb 8k TGA by a 800Kb 1k JPG? really?)
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OUTPUTS
  • Z depth pass
    - the Z depth channel is only tweakable if the render is still loaded in the framebuffer. if you use the batch render feature, you can't define the depth range. Therefore, you can configure Thea to output the depth pass as a thea img and once the renders are finished, open the thea img in thea studio, and tweak the depth ranges in the darkroom.
    - don't forget to delete the thea img afterwards as these tend to clutter your hard disks quickly.

    Position pass
    - it's recommended to save the position pass in exr 32bit if you plan to use it in post-production.

    Multichannel EXR
    - if you plan to use it in Photoshop, try the OpenEXR plugin otherwise PS can't load it and you end up with only the beauty pass and a very heavy file.
    - I have 32Gb and 80% RAM allocated to PS and still, some EXR are too heavy and take 10+ minutes to load.
    Therefore I only use multichannel EXR on small projects with few channels. With a good PS action, it's very fast to create a multi-layered psd file from separate passes.

    PNG with alpha (transparency)
    - By default Thea doesn't save as PNG with alpha. that means that the PNG keeps the backdrop.
    - if you want to get rid of the backdrop, you must activate the alpha channel in Channels tab, and then save the image as PNG. Now the backdrop won't appear when opening the PNG in Photoshop.

    Mask channel
    - I've finally got a grip of how it works, but its use is unfortunately not perfect yet. The biggest flaw is that you can't get masks of proxies (if you have the habit of using lowpoly proxies for trees, people, cars, shrubs, furnitures, etc. then you're stuck); you need real geometry;
    - furthermore, you need to create groups to use them; right-click on the group and select thea render->mask #1-#5 (#15 since RV444.1442). Now if you tick Mask in the Channels tab, you're supposed to get clean B&W masks.
    - you can't make a multi-selection of groups to attribute a mask# at once; you need to select them one by one, even if you want to attribute them the same mask id. Boring.
    Example: you have several cars on a road, and want to attribute mask#1 to the cars and mask#2 on the road. you select all, remove the road from the selection to keep only the selection of the cars. You can't attribute the mask#1 on the cars unless you select them one by one OR recreate a group of the cars. This is a handicap if you don't want to group the cars (for whatever reason).
    - you lose the mask of a mesh if you nest it in another group with another mask#.
    Example: if mask#1 window glazing mesh is nested inside a mask#2 window frame, the mask#1 won't be rendered.
    - thin glass meshes seem to render very weak contrast masks. they are basically useless. Bummer. :thumbdown:

    Masks for architectural glass: often useful to enhance colour/reflections of glass in architecture
    - if you use non-refractive glass (single-sided glass), Thea doesn't generate any usable masks for the glass (Object Id/Material Id won't record glass mesh/material) with Presto engine. Of course the refraction pass will remain black.
    - Use of refractive glass (2 sided glass and glossy shader) will allow for reflection/refraction passes and a usable mask in Obj Id/Mat Id, at the cost of more rendertime and darker interiors.

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WEIRD BEHAVIOUR
  • Oversized components: (fixed with RV444.1442 but I leave the debugging pattern if you happen to notice that on old files) sometimes weird huge mesh appear in the scene at rendertime. By further examination you can notice that the huge mesh is a part of a thea component but overscaled and merged with another mesh.
    - this is actually a naming issue; there is a group/compo in the skp file used to create the thea component that shares the name of another group/component that is used in the scene (like group#112 or component#58).
    - the solution is to rename the group/compo that gets replaced by the gigantic mesh at rendertime.
    or, if you're patient, rename the constitutive part of the skp component which has been used to generate the thea component (and of course update the thea component)

    Darker renderbuckets: during network bucket rendering, some buckets appear darker than the others
    - this is caused by a missing texture map, a map that the master workstation can find but not the slaves.
    - perhaps a network universal path problem (double check the console, and the thea browser's model info window); a local drive (Z:\\ or E:\\ that the slave can't access or find on the network)
    - sometimes SketchUp uses internal maps that aren't visible to Thea. It is the case when you "make a unique texture" by skewing/distorting an imported texture (from Streetview or GoogleEarth for example). SketchUp keeps using that generated texture without actually exporting it to allow render engines to "see" it. Solution: double-click the texture with thea material cursor, open the mat-lab and open the diffuse slot, copy the SUdef.jpg map to the project folder (or any appropriate folder), rename it with a meaningful name (not SUdef#5 copy) and finally put it in the diffuse slot. Accept the changes made and close the mat-lab. Voilà.

    NO LIGHT or NO GLASS?
    - Usually Thea is pretty tolerant with reversed faces (wrong normals) and even uses the reverse face material if the correctly faced side doesn't have any material mapped. BUT the emissive light material and transparent/refractive materials are the exceptions.
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MODEL CONVERSION Workflow from 3DSMAX
Basically the Convert2Thea script in Thea4Max works relatively well. BUT it's not failproof.
This is my usual workflow fyi.
  • 1. Assets Definitive Location: decide where you will finally keep the textures (on which drive, in which directory, folder tree, etc.)
    BTW it's a good habit to keep the textures next to the thea model.
    Copy the maps in that folder, if you decide to move them from the original folder.

    2. Asset tracking: In 3DsMax (shift-T), select all maps and right-click and choose "set path", then direct the path to the place where you copied the maps in 1.
    If you use a network folder (a drive on a network server) use the correct network path (not a drive letter like C: or Z:) . Then all the maps will be found automatically.

    3. in the material editor (I use Slate for that purpose), check all the shaders before conversion.
    - vray 2sided material: link directly the vraymaterial to the slot in multi/sub object material, thus bypassing the 2sided node. You can delete the 2sided node;
    - color correction: wether bypass it completely or keep it (converter will create a new bitmap)
    - blendmaterial: converter only keeps the first component
    - fallofs: bypass fallofs
    - vraynormals: bypass the vraynormal node (keep note that you will have to activate the "normal" tick in thea on the bump slot). If you keep the vraynormal node, the bump map will be totally ignored in the conversion so you'll lose the map path.
    etc.

    4. right click, open thea tools and use material converter.
    For the sake of security, direct procedurals and unknown maps to the path where you copied the maps in 1. so the color corrected maps, gradient maps, etc. will output there.

    5. open render setup window (F10) and choose thea render as renderer, and in the thea render tab, in the slot "On Render", choose export and do nothing, then create a preset for this setup, give an output name and path, and finally press Render.

    6. Launch Thea Studio, open the scn freshly created and verify if the textures have correctly been retrieved.
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RENDER SETTINGS IMPORT/EXPORT

To export render settings, environment, display, etc. from one file to another (Tomasz):

Open the Ruby Console to copy all those settings at once, but please be careful with this:
  • 1. Open your source skp model. Do not open Thea windows.
    2. Paste this in Ruby Console and press Enter/Return:

    data={};Sketchup.active_model.attribute_dictionary("TH4SU_Settings").each{|key,value| data[key]=value}

    3. Open a target model, without closing current SketchUp instance and paste this in the Console:

    dict=Sketchup.active_model.attribute_dictionary("TH4SU_Settings",true);data.each{|key,value| dict[key]=value}


    4. You can open now Thea windows and find your settings transferred.
Please note that all Camera/Display/Environment/Rendering/Channels/Animation settings will be overwritten in the target model.

Consider it as a temporary solution, until a proper one will be added to the plugin.

To define default thea render settings (like to have IR MC with 128s/p and CPU(max)+GPU by default instead of Unbiased?), just create a blank skp template, with all the thea settings you want by default and save it. If you want, you can even create several template skp files according to the type of thea render settings you want to begin with, depending of the project. Just configure SketchUp to ask you which template to open when creating a new skp file.

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MOVING THEA FOLDER

To move default Thea data folder from user account (C:\Users\username\AppData\Local\Thea Render):
Use Thea Studio Safe Mode option.

1. Move Thea Data folder to the new location
2. Start Thea Studio (Safe Mode). click OK
3. Browse to the new location (e.g. C:\TheaData or any folder you desire where user account has read/write)
4. to set write permissions to that destination properly in Windows 10, right click on the folder and in the Security tab review the current accounts that have access to that folder

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Official Thea Tutorials repository
I post them here because I'm lazy. :D

Tricks to expose interior images correctly vs sun light:
https://www.thearender.com/resources/Ac ... posure.pdf
Tips for interactive Thea lights tweaking (by George):
https://www.youtube.com/watch?v=wpfxLgbsSyQ
Differences between Render engines:
https://thearender.com/site/index.php/features
Last edited by quickit on Mon May 22, 2017 12:14 pm, edited 28 times in total.
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Rombout
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Be careful when over the exposing a image and save it as jpg or png. They don't have enough information to get light info back, save it as ear or HDR then if you want to use such tricks.

I would make your text above better and easier readable by making all the section in bold and understrike. Than perhaps use bullets to make separate point or paragraphs. Now it's simple a whirl of text and not quite read friendly. Sorry I'm graphic designer I tend to look for such things
quickit
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Hi Rombout,

Actually my post about noise isn't really a tip. I copy-pasted it from theastudio thread because nobody answered on that question and was sure that thea sketchup crew was more active :D
  • So, yes, you're right. I realized that noise in Thea isn't exposure-related so it's better to UNDEREXPOSE a render to keep the hilights (if you use clamp level 1.00 it's even more critical) and then correct the exposure by a curve/gamma in photoshop.

    And I'll try to keep the text graphically clean.
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There many threads about noise with lights and presto, did you try a search?
quickit
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Rombout wrote:There many threads about noise with lights and presto, did you try a search?
yes, indeed but there are so many. and my purpose in this thread was to keep all the good practices (noise is only one issue amongst others) in ONE thread. :D

I know, it's a bit presomptuous to write that, but crawling through ALL those threads is really time consuming when you're looking for simple infos.

Don't hesitate to share your tips, I'll update the first post with useful infos !
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nigec
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I'm very economical with lights/emitters, also relight can be your best friend figuring out were the noise is coming from
I don't use ies lights at all, usually my light sources are a simple triangle, if it was a ceiling light the light source is usually outside the light unit and a passive emitter to light it up
I don't have the fastest computer so I try to fake as much as I can, its rare I get noise, interiors light the scene like you would with a camera shot, the big risk is you can totally lose natural shadows if you over light the scene.

Noise with exteriors try a different sky, it is possible the hdri could cause noise
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Yes a lot of hdri cause noise but most of the time those are fire flies or hot pixels. This I due to the sun being to bright. You fix this by editing the sun a a editor of choice and than dark Ning the sun just a bit. Do mind not to over do this, it will cause you to loose your lives shadows if done to much
quickit
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nigec wrote:I'm very economical with lights/emitters, also relight can be your best friend figuring out were the noise is coming from
I don't use ies lights at all, usually my light sources are a simple triangle, if it was a ceiling light the light source is usually outside the light unit and a passive emitter to light it up
I don't have the fastest computer so I try to fake as much as I can, its rare I get noise, interiors light the scene like you would with a camera shot, the big risk is you can totally lose natural shadows if you over light the scene.

Noise with exteriors try a different sky, it is possible the hdri could cause noise
Can you post a visual illustration nigec? this is interesting.
quickit
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Rombout wrote:Yes a lot of hdri cause noise but most of the time those are fire flies or hot pixels. This I due to the sun being to bright. You fix this by editing the sun a a editor of choice and than dark Ning the sun just a bit. Do mind not to over do this, it will cause you to loose your lives shadows if done to much
It's a pity that Thea doesn't offer a gamma tweak for IBLs. It would allow us to dim the sun without having to open the HDRI in a dedicated software and reload it again.
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quickit wrote:
Rombout wrote:Yes a lot of hdri cause noise but most of the time those are fire flies or hot pixels. This I due to the sun being to bright. You fix this by editing the sun a a editor of choice and than dark Ning the sun just a bit. Do mind not to over do this, it will cause you to loose your lives shadows if done to much
It's a pity that Thea doesn't offer a gamma tweak for IBLs. It would allow us to dim the sun without having to open the HDRI in a dedicated software and reload it again.
Yes, I find that one big feature as well. Being to clamp or gamma, contrast etc the ibl would be great
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