Low Poly Mesh - Blender to Unreal [SOLVED]

[C_S]

Hi there,

I have a big issue with self made low-poly art in use with UE4.

I’ve done this nice set of low poly dungeon assets (unlit):

And here, lit lighting build, from above:

In Detail:

So my question is, what the hell is making the shadows so unnatural. I am very disappointed. I put hours in creating these assets and hours in search for finding a solution.

Problems: Shadows, seen on walls, are to “soft”, on the floor you literally see the different tiles because the lighting seems to render for one mesh lighter or darker in the whole part, if near or far to the lightsource.

Also Lamp shaddows are bad…

In Blender, I used this 256*256 Texture for all meshs:

I found out, that if i push the Static Mesh Ligh Map Resolution up, it gets a little bit better, but for massively increasing Lighting-Build-times. UE4 uses a resolution of 4 for my meshes (very low?!?). I overwritten it with 128 and 256. Going over 256 will increase rendertime massively.

Could the small uv-size be a source of this light(map?) problem:

You see, I scaled the uv-bits way down to fit in about 1 pixels x 1 pixels (it is the 256*256 texture from above). Is this texture too small?

I really need some help or some thoughts, were to start finding a solution.

Thanks!

[Mark_Jackson]

Not sure what the issue is here but when you mentioned scale, something sparked. Perhaps try changing the scene scale in blender to 0.01 and exporting out your FBX files again. This will make sure the assets match unreal scale (which is in centimetres compared to a blender unit being 1 metre by default).

[C_S]

Thanks for your ansper @Mark_Jackson, but this is what I ended up with:

It is just very small now

[FedPete]

Ask this question in the UE4 forum too!

[FedPete]

@C_S

You see, I scaled the uv-bits way down to fit in about 1 pixels x 1 pixels (it is the 256*256 texture from above). Is this texture too small?

Why? Because1x1 pixel uv-map, is basically giving a solid color to the objects face.
I understand you want to program this in UE4 in a quick way. But bad input gives bad output.
Try to deliver a clean, well configured .blend file.

• using correct world dimensions
• Good solid mesh (normal pointing the correct way)
• UV-maps in good optimum format.

[C_S]

Hi @FedPete,
thanks for your reply but I think I did not fully understand your answer here.

I used this Palette-technique learned by Imphenzia (Learn Low Poly Modeling in Blender 2.9 / 2.8 - YouTube). He scales the UVs to 0, this defintitly does not work with UE (result in black Materials). So i scaled up a bit. I learned, that Imphenzia is using Unity, where this does work.

• I am using correct world dimensions. A 1x1 cube in UE4 (Basic Actors) = A 1x1 Cube *.fbx from my blender config.
• All my normals are correct.
• What are UV-maps in a good optiumum format for you? What are you using?

[FedPete]

@C_S

I am using the correct world dimensions. A 1x1 cube in UE4 (Basic Actors) = A 1x1 Cube *.fbx from my blender config.

Blender default cube is 2x2x2 Blender units in the past but in the latest version 2m x 2m x 2m. Blender uses metrics, default 1 meter.
Blender objects and their internal mesh can differ in scale! That is why you need to apply scale for Blender.

@C_S

• What are UV-maps in a good optiumum format for you? What are you using?

A UV-Map is the conversion of a 3D object onto a flat 2D surface (bitmap).
The size of the UV-Mesh AND the size of the projected 2D bitmap, determines the size and dimension displayed (projected) on the 3D object.

A single FACE of a UV map, represents a single face on the rendered 3D object.
If a UV map face has the size of 1 pixel, that pixel is used (stretched, resized), to fill its related face object.

Game designers strive to configure the UV-mesh in such a way, that it uses the total capacity of the textured bitmap. In your case, if I see it correctly, I see 1% of the bitmap used by you UV-mesh.

@C_S

I used this Palette-technique learned by Imphenzia (Learn Low Poly Modeling in Blender 2.9 / 2.8 - YouTube). He scales the UVs to 0, this defintitly does not work with UE (result in black Materials). So i scaled up a bit. I learned, that Imphenzia is using Unity, where this does work.

I’ve no clue about this way of working. But then, I’m also not into game-related Blender development. So i know nothing about this trick. But I can imagine it will color UE4 objects in the same color. But Why using a color image and uv-mapping. Isn’t there a function in UE4 to give an object a basic color?

This is the Blender community, but I don’t know if many people do know about UE4.

[C_S]

I tried something and here is the result with all Lightmap Resolutions set to 256 (Default after import is 16 - way too low):

My conclution:

• Size of the UV-Textture-Mapping seems not relevant

• Custom UV Maps in Blender for Lighting
  
  → UV Mapping with “Lightmap Pack” in Blender, Margin 1 (smaller margin does a more ‘dirty’ shadowing)

• Resolution 256for Lightmap in UE4
  

  

Viewmode “Optimatiazion Viewmodes → Lightmap Density” gives me a solid green for “OK” on the Meshes:

[C_S]

Note: I also started using Blender Addon “Pipeline: Send to Unreal”

GIT HUB ← You must be loggend in to an Github Account, linked with Epic-Account to access link.

Unreal Article

[NP5]

Never heard of lightmap pack. Seems completely game related but never heard mention of it before.
Well done finding out all this game issue stuff.

[C_S]

@NP5 thanks!

Just hit “U” in Edit Mode and you will see the “Lightmap Pack” option

[Mark_Jackson]

Glad you found a solution to this. I did forget to mention that it also requires scaling things up again by 100, but anyway, in retrospect, I doubt it would have solved your issue.

Your solution is something I may perhaps need in the future with my game assets if I experience similar problems. Well done!

[C_S]

Hi there!

I finally found, what I was looking for the whole time . Here is the ultimate answer for all with the same problem:

https://youtu.be/yXi-e_ALnRs

This tutorial explains Lightmaps and why you need to do what to geht a propper result.

As showcase:

512 pxLightmap, without use of Seams in Blender and with use of “Lightmap Pack” (<- what is wrong!):

Difference:

And here finally with 128 px (!) Lighmap and propper Use of Unwrap ( + calculated margin 0.015):

I hope, I can help others with the same problem.

THREAD SOLVED.

[FedPete]

THX, so we can say, you’ve learned more than this course can give you.
A solution AND the skills to deduct a problem.

Well done !

[C_S]

Thank you, appreciate it!