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How to get alpha channel for background masking with LW?

Anonymous
Not applicable
How to get alpha channel for background masking with LW?
Maybe somebody knows!
13 REPLIES 13

fuzzytnth3
Booster
I'm pretty sure this hasn't been fixed yet

http://archicad-talk.graphisoft.com/viewtopic.php?p=25742&highlight=alpha+channel#25742
AC versions 3.41 to 25 (UKI Full 5005).
Using AC25 5005 UKI FULL
Mac OSX 10.15.7 (19G2021) Mac Pro-2013 32gbRam AMD FirePro D500 3072 MB graphics

Anonymous
Not applicable
are you sure your image has an alpha channel? if not, create it in photoshop

I haven't had problems with trees or people and when the alpha channel is shown with the image, I open it in Photoshop and create it

Anonymous
Not applicable
OK, Photoshop or other bitmap editor is good, but for different works. When I wrote about alpha channel for background with render from LW engine, I mean about automate alpha channel for background cutout, like standard GS engine (of course in bitmap editor).
For this time I create 2 images: one with LW engine, one with standard GS Render engine. From second I extract and use only alpha channel for masking first image.

Regards
Paweł

Anonymous
Not applicable
Sorry, Pawel, no way!

I going to post a question myself when two days ago I had to switch to 3dsMAX to make a very simple rendering which needed an alpha channel transparency. Which makes AC rendering obsolete!

This feature does not work in AC 8.0 or 8.1 either. I hoped they had fixed it in LW but .... (will be censored )

I hope Dwight could throw some light upon it. Please, Dwight, you are our only hope...

Anonymous
Not applicable
Here is a rendering done with lightworks where all the flowers and bushes have the alpha channel transparent, LW still needs work, but you have a 2d, 3d and rendering bundle
GOLD3a.jpg

Anonymous
Not applicable
Klimet you have right! - background alpha channel transparency doesn't work in AC9. I was write about old picture created at AC 7 and now rerendered with Ac9 and LW engine. After your post I tested AC9 and ......some censored words.

Klimet! - You can get alpha channel for background transparency straight from AC9 (only for old GS render engine). You must rendering your project with Background Transparency function ON an writing image as *.tif, millions of colours+. Next steps see my previous post.

Jugada, we are working witch trees, flowers and others bitmap with alpha channel transparency for background, but we are need for alpha channel for rendering background transparency (eg. sky) straight from AC.

Regards
Paweł

Dwight
Newcomer
I am stealing Pawel's background masking idea for the book. Excellent lateral thinking! Sometimes the old ways are best.

As for the mapping masking roughness - I do not experience this issue. The one time I descended into the poor taste depths (not that I haven't seen it done nicely) picture mapped plants, it worked fine.

I can suggest that perhaps your masks need work? I know - it worked fine before...... sorry.
Dwight Atkinson

Anonymous
Not applicable
Nice idea, Pawel, but when I try to render my model with the Internal Engine ("Picture" for backgroung colour and "Appha transparency" on) I get only the Backgroung picture without the model in my final render. Does the Internal Engine work with you?

Anonymous
Not applicable
Some examples for my idea! It works good.
First rendering options window, internal engine of course

Anonymous
Not applicable
Part II.

Anonymous
Not applicable
Part III. Result.
This is tiff file compressed with ZIP. This file included excellent alpha channel mask for background. Now with bitmap editor eg. Photoshop or PSP (I use last), we can extract alpha channel and add to LW image.
Regards
Paweł

Anonymous
Not applicable
I don't know but probably all problem background alpha channel is related with Graphic Card! Today I tested AC in office where is installed GForce - and alpha channel is missed. This same project rendered in my home where is installed ATI 9200 - I have got alpha channel. Is it possible? Work environment is this same on both machines, materials and others options too.

Regards
Paweł

Anonymous
Not applicable
The steps you described are exactly the same I did with my rendering, but alpha is still missing. I don't know if it is the video card - I was trying this at home with NVidia GForce II. Anyway, is it a silly bug that makes me go to Max (in fact it made me go to Max a long time ago).

By the way,Pawel, it is better if you use Targa instead of Tiff+. It comes without background then you open it in Photoshop and saves you several steps like loading selections and so on.

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