Search in
Sort by:

Question Status:

Search help

  • Simple searches use one or more words. Separate the words with spaces (cat dog) to search cat,dog or both. Separate the words with plus signs (cat +dog) to search for items that may contain cat but must contain dog.
  • You can further refine your search on the search results page, where you can search by keywords, author, topic. These can be combined with each other. Examples
    • cat dog --matches anything with cat,dog or both
    • cat +dog --searches for cat +dog where dog is a mandatory term
    • cat -dog -- searches for cat excluding any result containing dog
    • [cats] —will restrict your search to results with topic named "cats"
    • [cats] [dogs] —will restrict your search to results with both topics, "cats", and "dogs"

Office Holiday

Epic Games' offices will be on holiday from June 22nd to July 7th. During this period support will be limited. Our offices will reopen on Monday, July 8th. 

Overlapping UVs in Open World Demo Collection

I've been playing around with the assets found in the Open World Demo Collection, and they seem to be pretty nice in general. However, the trees have overlapping UVs. What's more, since 4.7 got rid of the "Generate Unique UVs" option in the Window menu of the static mesh editor, I don't have any way of fixing this.

Product Version: Not Selected
more ▼

asked Apr 07 '15 at 11:57 AM in Rendering

avatar image

161 13 14 17

(comments are locked)
10|2000 characters needed characters left
Viewable by all users

1 answer: sort voted first

Hi Fibericon,

You are still able to generate Lightmap UVs in the editor. The process changed in 4.5 when the new method of generating lightmaps was introduce.

You can follow these steps to generate your lightmap UVs: https://wiki.unrealengine.com/LightingTroubleshootingGuide#How_do_I_generate_lightmap_UVs_in_the_editor.3F

Also, which tree is giving you the issue? I can take a look on my end and offer some help if there is an issue.

Thank you!


more ▼

answered Apr 13 '15 at 08:17 PM

avatar image

Tim Hobson ♦♦ STAFF
48.8k 887 101 878

avatar image fibericon Apr 14 '15 at 04:11 AM

The tree in question was HillTree_02. I was using a foliage brush to place them, if that makes a difference.

avatar image Tim Hobson ♦♦ STAFF Apr 14 '15 at 09:15 PM

Looking at the asset, which was designed no originally to be used for static lighting, is generating an overlapping error. Unfortunately, this is not a bug, it's just a limitation of the way UVs are generated in the editor. In order to completely remove that error you'll need to take the asset into a modeling program and fully edit the UVs for Channel 1.

On the plus side, this is just a warning as well and there is only 2.8% overlapping faces, which is not a lot when you consider that this is a 50k triangle mesh. I re-generated a lower lightmap resolution of 256 and built lighting without noticing any artifacts. Ultimately, you can ignore the warning unless you see any significant issues.

Again, this wasn't originally built to be used for this purpose. These assets are meant to work with dynamic lighting since you would want the leaves and smaller branches to sway with wind in the engine.

I hope this helps.

avatar image DocRogers Apr 19 '15 at 04:26 PM

Hello Tim,

I am having a unique error with this specific tree in 4.7.5.

I can't even open the details for this SM as it causes my UE4 to hang and requires me to force quit. I've tried to let it load for a few minutes but I just can't ever get this tree open. As well as HillTree_Tall_02. So far these seem to be the only ones that are hanging up my editor. There are still a lot of assets I need to pull through. I'm hoping these are the only 2 assets that are causing this problem.

I know I need to edit the Light Maps for a lot of the KiteDemo stuff and I have done that successfully on the few assets I have used from this particular content folder. I can get around not using these two tree assets, but they would look really good with the plateau I am working on. As I am typing this I am still letting the editor load the Tree but it gets stuck at 74% and 99%.

Will I need to go into a modeling editor to fix the UV channel 1 as you mentioned above? I am using dynamic lighting in my level. I understand that these assets were designed for static lighting. If I were to switch to static lighting within my world could that alleviate the hang ups that these two SMs are causing? Or should I be using them with a Foliage Brush as the original poster mentions how he was using them?

I'm just curious why these trees would cause my editor to hang when trying to edit them and/or place them into my world. I have a great system so I can't think it would be my hardware. But I will post my specs if that will help.

i7 4790K 4.0 Ghz 16 GB RAM ASUS Maximus VII Hero Z97 EVGA GTX 980 SC Editor is installed on my 500 GB SSD Unreal Projects are written to my 2TB HDD.

Thanks for any insight you can shed on this for me.


avatar image Tim Hobson ♦♦ STAFF Apr 20 '15 at 01:35 PM


I just want to preface this with the notes included with this content on the Marketplace:

alt text

These assets take a while to open. Even on my machine here and I'm running a high-end machine and these assets can take a while to open for the first time.

It may appear as if the engine has "frozen" but it's just writing the data cache for the assets. You will need to wait it out for the process to finish. After this initial load it should be much quicker placing additional ones. It's just the initial load of such a highly detail asset and texture.

Will I need to go into a modeling editor to fix the UV channel 1 as you mentioned above? I am using dynamic lighting in my level. I understand that these assets were designed for static lighting.

If you're using Dynamic lighting you DO NOT need to worry about lightmaps. These assets were actually designed for Dynamically lit worlds such as the GDC Kite World demo. These assets were made to be mostly compliant with static lighting when preparing them for the Marketplace.

If you decide to use them for static levels, you will need to correct the UV overlap in a modeling application or if you can live with the ~2.8 % overlap, which is negligible, it won't be so bad. It'll just be a warning that displays in the error messages after you rebuild lighting.

As for using static lighting in large worlds, I would not recommend it necessarily. If you're creating a highly detailed world this will probably cause more frustrations and hangups with the process than using dynamic lighting. This is why you often see larger worlds that use Dynamic Lighting over static lighting (Fallout, Skyrim, GTA, Assassins Creed).

high-end.png (17.2 kB)
avatar image Yipeee Oct 23 '15 at 11:06 PM

Hi Tim, I'm running into the same overlapping UV problem with the HillTree_02 asset in 4.9.2, but it says it's an error and not a warning. I've unchecked Cast Static Shadow in the Foliage Asset that uses HillTree_02, but that doesn't seem to fix the problem. Any ideas?

(comments are locked)
10|2000 characters needed characters left
Viewable by all users
Your answer
toggle preview:

Up to 5 attachments (including images) can be used with a maximum of 5.2 MB each and 5.2 MB total.

Follow this question

Once you sign in you will be able to subscribe for any updates here

Answers to this question