We're sorry Aspose doesn't work properply without JavaScript enabled.

Free Support Forum - aspose.com

Apply different material / texture to different sides of a mesh

I have a mesh which has been loaded from an external resource, and I need to be able to apply 2 different materials / textures to 2 different “surfaces” on the mesh. So picture a cube mesh, where the 2 triangles representing one face of the cube displays picture A, and another face displays picture B.

The textures are determined at runtime so trying to do a wrapped texture is not an option.

I have all the code working to be able to calculate the UV’s for any given vertex on the face; the piece I can’t seem to figure out is how to set up the vertex elements with your (somewhat confusing / inscrutable) MappingMode and ReferenceMode paradigms.

Is there any chance you have any, or could write, some example code showing how to build a simple cube, and apply 2 different materials / textures to 2 different faces on the cube? It would be INCREDIBLY helpful. All my outputs are in GLB, if that makes a difference.


Thanks for contacting support.

We are looking into your inquiry and checking related information at our side. We will get back to you shortly with our feedback.


Please find attached sample code for building a simple cube with different materials on different faces and save to .gltf.SampleCode.zip (1.6 KB)

Hi asad.ali, I’m interested in this sample code but I cannot download the attachment because it’s restricted to the topic owner. Could you share it with me please? Thank you!


Below is the code snippet content from above file:

using Aspose.ThreeD;
using Aspose.ThreeD.Entities;
using Aspose.ThreeD.Formats;
using Aspose.ThreeD.Shading;
using Aspose.ThreeD.Utilities;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;

namespace Test
    class SampleCode

        public static void CreateBoxWithDifferentMaterials()
            var box = new Mesh();
            var controlPoints = box.ControlPoints;
            controlPoints.Add(new Vector4(-5.0, 0.0, 5.0, 1.0));
            controlPoints.Add(new Vector4(5.0, 0.0, 5.0, 1.0));
            controlPoints.Add(new Vector4(5.0, 10.0, 5.0, 1.0));
            controlPoints.Add(new Vector4(-5.0, 10.0, 5.0, 1.0));
            controlPoints.Add(new Vector4(-5.0, 0.0, -5.0, 1.0));
            controlPoints.Add(new Vector4(5.0, 0.0, -5.0, 1.0));
            controlPoints.Add(new Vector4(5.0, 10.0, -5.0, 1.0));
            controlPoints.Add(new Vector4(-5.0, 10.0, -5.0, 1.0));

            // Create polygons to mesh
            // Front face (Z+)
            box.CreatePolygon(0, 1, 2, 3);
            // Right side (X+)
            box.CreatePolygon(1, 5, 6, 2);
            // Back face (Z-)
            box.CreatePolygon(5, 4, 7, 6);
            // Left side (X-)
            box.CreatePolygon(4, 0, 3, 7);
            // Bottom face (Y-)
            box.CreatePolygon(0, 4, 5, 1);
            // Top face (Y+)
            box.CreatePolygon(3, 2, 6, 7);

            //To simplify the demo we generate the normal and uv automatically instead of 
            //writing a lot of code here, it's not perfect but enough for demostration.

            //in order to generate UV automatically, normal data are required.
            var normals = PolygonModifier.GenerateNormal(box);

            //generate UV
            var uv = PolygonModifier.GenerateUV(box);

            //create node and scene that owns this box
            var scene = new Scene();
            var node = scene.RootNode.CreateChildNode(box);
            //prepare materials to the node
            node.Materials.Add(CreateMaterial(Color.CadetBlue, "Mat-1"));
            node.Materials.Add(CreateMaterial(Color.Goldenrod, "Mat-2"));
            node.Materials.Add(CreateMaterial(Color.FloralWhite, "Mat-3"));
            //assign materials to different polygon by using VertexElementMaterial

            var mats = (VertexElementMaterial)box.CreateElement(VertexElementType.Material);
            //Default mapping mode for material is AllSame
            //we need per polygon material
            mats.MappingMode = MappingMode.Polygon;
            //assign material indices to the polygons so that
            // Polygon 0 - 2(Mat-3)
            // Polygon 1 - 1(Mat-2)
            // Polygon 2 - 0(Mat-1)
            // Polygon 3 - 0(Mat-1)
            // Polygon 4 - 1(Mat-2)
            // Polygon 5 - 2(Mat-3)
            mats.SetIndices(new int[] { 2, 1, 0, 0, 1, 2 });
            //save to glb
            var opt = new GLTFSaveOptions(FileFormat.GLTF2_Binary);
            opt.EmbedAssets = true;//the output will embed the textures
            //The GLTF's structure of this box contains 3 primitives which uses different materials
            scene.Save("cube.glb", opt);

        private static Material CreateMaterial(Color color, string text)
            //create a texture using System.Drawing
            //just a plain color background with a text on it
            var tex = new Texture();
            tex.FileName = text + ".png";
            using(var img = new Bitmap(128, 128, PixelFormat.Format24bppRgb))
                using (var g = Graphics.FromImage(img))
                    using (var font = new Font(FontFamily.GenericSansSerif, 20))
                        g.DrawString(text, font, Brushes.Black, new Point(0, 0));

                //embed the image as png format to the texture
                using (var ms = new MemoryStream())
                    img.Save(ms, ImageFormat.Png);
                    tex.Content = ms.ToArray();
            //create an empty material to use this texture
            //when the scene get exported to gltf/glb 2.0, Aspose.3D will convert non-pbr materials to pbr materials
            var mat = new LambertMaterial();
            mat.SetTexture(Material.MapDiffuse, tex);
            return mat;


Thank you very much