generating 3d texture on script

        var info = new RenderTextureDescriptor();
        info.dimension=UnityEngine.Rendering.TextureDimension.Tex3D;
        info.colorFormat = RenderTextureFormat.ARGB32;
        info.width = 512;
        info.height=256;        
        info.volumeDepth=90;
        info.depthBufferBits = 0;
        info.msaaSamples = 1;
        info.mipCount=0;
        _rt3d=new RenderTexture(info);
        _rt3d.name="TEST3DTEX";
        _rt3d.Create();