Dear all,
i have an issue when i import a texture that i made in Photoshop (2022) to Unreal. Even though I did not add an alpha channel in Photoshop, Unreal keeps adding an Alpha channel when I import the texture (“Has Alpha Channel: True”). This doubles the size of the texture and happens for like 20 texture already…
I use tga 24 bit, but have also tried jpg and png, with the same result.
I use UE 4.26
Is there anyone who could help me? Thank you so much!
Tom
Hi Tom - you can easily remove alpha channels with the Bulk Property Editor, select them all, open that and tick “Compress without Alpha”
Thank you! I did that now with the bulk editor (didnt know bulk editing existed) and ticked “compress without alpha”.
I knew about the compress function in general before and i heard in a video on youtube that it only compresses the textures when “cooking” them. Is this true? The size of the texture is currently not reduced in UE 4.26, so I assume there is no immediate effect when ticking “compress without alpha” (I have seen a vid in UE5 and texture size reduced.). If my understanding is correct, I am not entirely sure when cooking exactly technically happens. Currently I only work in the editor and click the “play” button. I assume no cooking happens here and i need to go further. Do I assume right? The problem is, that i reach the RAM limit already in the “play” mode. I hope you understand what I mean.
Thank you again and in advance for any feedback!
You should see a reduction immediately when ticking that option - it won’t reduce the size on disk, just in VRAM - if you open a texture you can see that in the details panel:
As far as cooking goes - that might be talking about Max Texture Size or LODbias settings - they get cooked at the build stage so you wouldn’t see any reduction there until then.
But changing that option, or the compression type you should see a change in the VRAM used immediately.
There are a number of other things you can do to reduce memory, I’ve got a few tutorials at (check the menu running down the left side):
They apply in general, but are focused on a tool I have on the marketplace, rdTexTools - that allows you to do quite a few things to reduce the VRAM used.
Thank you again, much appreciated! Thats unfortunately exactly the problem. I tick compress without alpha and there is no immediate effect in the “Resource Size” field. The size stays the same. I saw on YT that there is immediate effect in UE5, but I use UE 4.26, because in UE5 i get a very bad framerate. Do you use UE5?
That is why i initially asked, if i can import my texture files (which do not even contain alpha channels) in a way, that UE4 does not generate alpha channels afterwards. I want the “Has Alpha channel” field to be “false” straight after import.
I think i ran into a very complicated issue…
Thank you for the tutorials and the link to the tool. I will definetely check this out as soon as i find the time for it!
.
I use UE4 as well, and it works as expected when I do it - just tested importing images from Photoshop with and without Alpha and they worked correctly - are you using the “Quick Export as PNG” option?
Is your “Compression Settings” set to “DXT1/5”? That’s BC1 compression and will compress in the VRAM most efficiently.
Having a look at your snapshots there - you’ll get the ability to MipMap if you change the size to a “Power of 2” - for example, resize to 2048x2048 pixels - that will save you a lot of VRAM - without MipMaps, the whole texture will always reside in VRAM.
thank you again!
I saved them as targa files 24 bit. I also tried jpg and some other file formats, always with the same results. I even used two different versions of Photoshop (Photoshop 2022 and a very old version CS3).
Yes, the Compression Settings are set to DXT1/5.
I think i will reduce the resolution in Photoshop for these textures as soon as i fixed the alpha issue. I did the “Power of 2” technique also already for 4k and 8k textures i downloaded in the past. This helped a lot already.
I wonder if you can change the import settings for textures in UE4 somwehere? Otherwise, i really have no idea what else i could do…
Maybe a good test is to try and import the image below and see if it has an Alpha channel? This is the one that imports without one from here…
Hi, did you Right-Click the image and “Save Image As…”? It should have the size 2048x2048, screen scraping it will not preserve the file format…
sorry for the inacuracy. I saved it only in preview mode. Now as I saved the whole picture it shows "has alpha channel " as FALSE!
What I did next was opening your red dot texture in photoshop and saved it again as a png under another name, imported it into UE4 again and it still shows "has alpha channel " as FALSE. Its an rgb 8 bit file.
However, when i save another texture with the same settings and as an rgb 8 bit file, this texture gets an alpha channel in UE4… in Photoshop it does not have an alpha channel:
This is so weird and frustrating.
addition: when I copy in my texture into your red dot texture and save it as a new png, it will also show an alpha (“True”) in UE4.
It sounds like it’s something in Photoshop - possibly the default settings for export, this is what mine look like, but you could try unticking the “Transparency” box.
I have had issues similar when just using “Save As” - but the Export option works well…
thank you, i use exactly the same settings.
The good thing is, i just created a complete new texture from scratch. When i export it as a png an import it into UE4 it will show the alpha as FALSE. I hope this will be the case for all new textures and that the situation will be stable.
I still need to find a solution for my old textures, which i made a longer time ago and where the issue remains. The weird thing is that when i copy the whole texture into a new file created from scratch, the issue will appear again. I thought i can fix it this way and wonder why this is not the case, but for now i will no longer follow this problem.
Thank you again. In the WWW I have not often met a person as helpful as you. I really appreciate this and your very helpful character!
Photoshop will always export a texture with an alpha channel unless;
Photoshop’s deprecated methods of exporting files (Save, Save As… and Save a Copy…) will always save with an alpha channel.
Please use the above instructions to use the newer export methods to save without an alpha channel.
I have an exr with no Alpha channel, however Unreal seems to create one upon import
Compress Without Alpha not working on HDR(RGB, no sRGB) is not working?
This does work with other compression settings but it is HDR(RGB, no sRGB) that I need.
I understand the this channel is Alpha channel doubling it’s “resource size”?.. So it would be great to remove it if possible?
