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architecture rendering
About Truespace Archives
These pages are a copy of the official truespace forums prior to their removal somewhere around 2011.
They are retained here for archive purposes only.
architecture rendering // New Users
Post by andras // Feb 18, 2008, 12:31am
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andras
Total Posts: 111
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Hi!
How can I place my render picture into backroud (with compositing or...within truespace 7.5 or photoshop/Gimp)? And Where and how can I set the alpha channel in rendering ? The Gimp dont see the alphachanel.
(sorry for my many question:) ) |
Post by prodigy // Feb 18, 2008, 1:24am
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prodigy
Total Posts: 3029
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Andras..
First all depends if you need to work in Worskpace or Model Side..
Both side has diferents way to set an image as background.
*Model Side (you can render on Vray, Lightworks and in Realtime preview)
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First you need to click on the Background Effect shader, then Right click over that icon and select your background image.
After that, Right click over any of the draw objects tools (top right yellow square to open the display options) then click over the Show background icon to watch your image in realtime mode..
*Workspace side (only if you render with Vray) workspace has no realtime background preview. :(
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Post by parva // Feb 18, 2008, 1:38am
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parva
Total Posts: 822
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Hi!
Where and how can I set the alpha channel in rendering ? The Gimp dont see the alphachanel.
save your image as TGA 32 bit and you get alpha. |
Post by prodigy // Feb 18, 2008, 1:39am
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prodigy
Total Posts: 3029
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Ups.. i miss that answer :D
Thanks Parva |
Post by andras // Feb 18, 2008, 2:04am
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andras
Total Posts: 111
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Thanks, I use V-ray in Workspace but the How can I save TGA 32? I find only TGA without 32:( on V-ray "save picture" menu.
And this is not works.
So the TGA is work as alpha channel material , but it is not work as saved finalrender image. (anyway I use Gimp, no photoshop) |
Post by prodigy // Feb 18, 2008, 2:09am
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prodigy
Total Posts: 3029
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Any tga saved on workspace side is a 32bit tga with alpha channel.
Btw, tellme if you are using antialiasing... there's a knowed issue with tga alpha and antialiasing. |
Post by andras // Feb 18, 2008, 3:01am
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andras
Total Posts: 111
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Yes, I use AA |
Post by prodigy // Feb 18, 2008, 3:27am
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prodigy
Total Posts: 3029
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Try to use adaptive only.. |
Post by andras // Feb 18, 2008, 3:34am
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andras
Total Posts: 111
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:( it is not working
with blender
http://www.andras2.extra.hu/1.JPG
http://www.andras2.extra.hu/1r.JPG
with truespace No AA
http://www.andras2.extra.hu/2.JPG
http://www.andras2.extra.hu/2r.JPG
with truespace with adaptive AA
http://www.andras2.extra.hu/3.JPG
http://www.andras2.extra.hu/3r.JPG |
Post by prodigy // Feb 18, 2008, 4:04am
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prodigy
Total Posts: 3029
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Wierd, working here.. |
Post by prodigy // Feb 18, 2008, 4:08am
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prodigy
Total Posts: 3029
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Ho by the way.. there's another issue.. maybe that's the problem
Save your tga with diferent names... if you save your tga as test.tga with AA and next the same render (or not) without AA with the same name (test.tga) the last render was not saved.. so you need to save your tga as test1.tga to watch those changes.. |
Post by andras // Feb 18, 2008, 4:34am
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andras
Total Posts: 111
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So, If I use AA the alpha channel is not woking?
(Sorry for my english : issue mean "problem" or "bug" in this case? )
anyway I tried your zipped untitle.tga but no changing :( |
Post by prodigy // Feb 18, 2008, 4:44am
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prodigy
Total Posts: 3029
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Yup... It's a very nice bug...
Don't worry about your english.. my english is the worst on the community :D
My tga, has alpha channel.. if you can seeit there's something wrong on your 2d software or when you extract the alpha..
Don't realy know, but that tga has alpha channel. |
Post by andras // Feb 18, 2008, 5:03am
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andras
Total Posts: 111
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Hmmmm....:jumpy:
AAAchannel, Transparent Shadow, Caustics ...are there anything fineness? |
Post by andras // Feb 18, 2008, 5:18am
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andras
Total Posts: 111
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Otherwise, is your TGA file would be as my first result with Blender? |
Post by andras // Feb 18, 2008, 6:38am
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andras
Total Posts: 111
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OK. I realised that GIMP is not support TS's TGA instead of this have to use PS, inkspace or other. Or I can't set GIMP
AND TS's TGA is looks like better than Blender's |
Post by TomG // Feb 18, 2008, 6:40am
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TomG
Total Posts: 3397
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I can confirm that Prodigy's TGA does have alpha information in it. If you are not seeing the alpha information, then this is part of the 2D software, rather than how tS is exporting the information, as the alpha information is definitely in there.
The file is 32 bits per pixel, not sure if you have any import settings to govern how the GIMP loads TGA. Perhaps some GIMP users can comment. Note that Prodigy's file does NOT have RTE compression on it, again not sure if that affects how the GIMP processes the file.
I attach a zip with a 32 bit version with compression, and a PNG version (PNG also contains alpha information so you may want to try that). These are converted from Prodigy's version and it would be interesting to see if either loads better :)
HTH!
Tom |
Post by andras // Feb 18, 2008, 7:16am
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andras
Total Posts: 111
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Yes, I agree . I look for another opensource photoshop. |
Post by TomG // Feb 18, 2008, 7:23am
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TomG
Total Posts: 3397
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One other quick note just for interest while I think about it - if you use Anti Aliasing, then the edges of the object become blended with the background color, to make them smooth.
Now, that leads to a problem with alpha - if you blend the object edge with the background color, then when you drop it into another image, it will have a "halo" around the edge that contains the background from the render. This makes the object unusable for any purpose that you might want it to have an alpha map, as the background color will still be stuck in there around the edge.
You can see this effect by rendering with anti-aliasing and using a select tool in an art package to cut out the object and paste it onto a different colored background. You'll find the original background color has "bled" into the object and the result does not look good.
So for that reason, to render with an alpha channel, you need to disable anti-aliasing. Just in case anyone was interested in why it is set up this way :)
Do let us know how you get on with the software - you could render to PNG and see if GIMP works well with that. I am pretty sure there must be other free software out there that will do the job too, any suggestions from folks?
Thanks!
Tom |
Post by Jack Edwards // Feb 18, 2008, 8:44am
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Jack Edwards
Total Posts: 4062
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PNG alpha works with both GIMP and TS/VRay last I checked. So that would be the way to go. ;) |
Post by andras // Feb 18, 2008, 8:51am
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andras
Total Posts: 111
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I know this probleme from blender. Unfortunately it is very annoying.
Finally I use Inkspace (GNU vector graphic appl.) to PNG export and import in Gimp. Unforunately I dont find good software for this purpose or that I found the design was not expectable for my taste. |
Post by Dirk_Fist // Feb 18, 2008, 4:57pm
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Dirk_Fist
Total Posts: 15
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Ok I don't have Vray, but lightworks 32bit tga render had an alpha channel, and gimp (version 2.2.17) loaded it without problem.
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You should be able to use anti-alias if the background color is the same (or nearly the same) as the object (this makes the *halo* part of the object and the alpha will blend into the background) |
Post by andras // Feb 19, 2008, 2:02am
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andras
Total Posts: 111
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I dont know where is the mistake in my settings in Gimp (2.2 or 2.4), because these are default. Certainly all the same, I solve the probleme with Inkspace export. |
Post by TomG // Feb 19, 2008, 5:33am
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TomG
Total Posts: 3397
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On the anti-alias issue, if you are placing an object onto a plain color background, then the alpha map isn't really required - you can render without an alpha channel and just use that background color :)
Usually the alpha channel is needed because the object will be placed onto a complex background that isn't a single color (eg photo, another rendered image, something with text, etc), or placed onto various backgrounds of different colors where you may not know all the colors in advance, and that is where the alpha channel comes in handy (and where the anti-alias halo becomes a problem).
Lightworks may well produce a different TGA format than V-Ray, I note that V-Ray is not using RLE compression and perhaps the GIMP doesn't load that up as a result. I'm pretty sure that the Lightworks output does use RLE compression in its TGA output. Were you able to load Prodigy's sample TGA into your version of the GIMP? If not, could you load the RLE version that I posted? That would let us know if it is indeed the compression issue that is making the GIMP trip up in this case :)
Thanks!
Tom |
Post by andras // Feb 19, 2008, 5:50am
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andras
Total Posts: 111
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Hi!
Yes, I tried both. Prodigy's sample is not work but yours works. |
Post by prodigy // Feb 19, 2008, 6:25am
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prodigy
Total Posts: 3029
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sniff... sniff.... why nobody like my tga :(
hehehehe... seems an issue with RLE compression.. good if vray support RLE Compression on the future.. |
Post by TomG // Feb 19, 2008, 6:31am
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TomG
Total Posts: 3397
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Issue solved in that case, the GIMP won't read uncompressed TGAs, so we know the cause :) Thanks for confirming that, always good to know the reason behind a problem, helps identify possible solutions!
Tom |
Post by prodigy // Feb 19, 2008, 6:33am
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prodigy
Total Posts: 3029
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Yup... an issue from Gimp's side :p |
Post by jamesmc // Feb 19, 2008, 7:35am
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jamesmc
Total Posts: 2566
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I have GimpShop which is based on Gimp. It's confirmed that is doesn't load the TGA properly.
However, one click with the magic wand and the background disappears (can even do it in layers after you copy the background layer or make a duplicate)
It does save out as RLE 32 bit TGA if you wish.
I prefer 32 bit png myself as there are less problems. |
Post by TomG // Feb 19, 2008, 8:15am
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TomG
Total Posts: 3397
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I was a big TGA fan in the day, for saving out final renders and frames for animation, as I wanted compression, but without loss in quality. However I too now prefer PNG, it gives better compression in my tests than TGA these days, and seems generally happier with Windows (I can see previews of PNGs but not of TGAs natively in Explorer etc).
So PNG would be my choice for an image format in most cases. At present though rendering from V-Ray does not let you add an alpha channel to the PNG format, so TGA is the only way to go for that, for now.
HTH!
Tom |
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