> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://help.sayduck.com/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# 3D Assets - Common uploading issues

This article will help you find solution to any common uploading issue. 

### Product uploaded with no materials

If no **Material** information is found in the uploaded asset, a default material will be created and assigned to your **Meshes**.

[Materials - What & How to use?](/en/article/materials-what-how-to-use-17i4pe/)

![](https://storage.crisp.chat/users/helpdesk/website/cae6f284ce714800/screenshot-2022-09-02-at-95954_1t1luen.png)

### Model uploaded with no layers (Mesh_1)

When uploading files with more than 25 meshes, the meshes will be either combined into a single mesh called **Mesh_1** or the upload will fail. 

To avoid this, you need to combine group layers into single meshes or export model in separate files. Always aim to have the least amount of meshes and materials for optimal performance. 

**Rhino** https://discourse.mcneel.com/t/merge-layers/2917
**Sketchup** https://forums.sketchup.com/t/how-do-i-ungroup-all-and-merge-all-layers/14388
**Blender**: https://all3dp.com/2/blender-how-to-merge-objects/

![](https://storage.crisp.chat/users/helpdesk/website/cae6f284ce714800/screenshot-2023-04-24-at-14064_7cn3ee.png)

### Vertex normals

When working with 3D, it's often necessary to use faces that are only visible from one side. This means that the other side is see-through or transparent. If you notice any areas on your 3D model that are transparent or appear darker than others, you may need to adjust the way the **Vertex normals** are calculated.

![](https://storage.crisp.chat/users/helpdesk/website/cae6f284ce714800/screenshot-2023-04-24-at-14231_54shih.png)

###  Smoothing groups

Smoothing groups are a way to make 3D objects look smoother and more realistic by grouping together parts that should look like a single smooth surface, so that they are shaded accordingly. This helps to eliminate the jagged and choppy appearance that can occur when shading is calculated independently for each polygon.

![](https://storage.crisp.chat/users/helpdesk/website/cae6f284ce714800/screenshot-2023-04-24-at-14104_1ahtu4z.png)

###  Texture does not look correct

If the textures you uploaded aren't displaying correctly, try turning on the **UV map** editor option. This will put a plain texture on your model and make it easier to figure out what's going wrong. When the UV maps are properly unwrapped, the pattern on the texture should be consistent throughout the model with no distortions.

![](https://storage.crisp.chat/users/helpdesk/website/cae6f284ce714800/screenshot-2022-08-16-at-13412_fhzset.png)

######  Pack UVs to 1:1 UV space

For CAD models, make sure that your UV maps are packed to 1:1 UV space.

![](https://storage.crisp.chat/users/helpdesk/website/cae6f284ce714800/packeduv_u5tlgc.jpg)