diff --git a/SabreTools.Models/BDPlus/SVM.cs b/SabreTools.Models/BDPlus/SVM.cs
index c38d1e6..284f036 100644
--- a/SabreTools.Models/BDPlus/SVM.cs
+++ b/SabreTools.Models/BDPlus/SVM.cs
@@ -1,3 +1,5 @@
+using System.Runtime.InteropServices;
+
 namespace SabreTools.Models.BDPlus
 {
     /// <see href="https://github.com/mwgoldsmith/bdplus/blob/master/src/libbdplus/bdsvm/loader.c"/>
@@ -6,40 +8,39 @@ namespace SabreTools.Models.BDPlus
         /// <summary>
         /// "BDSVM_CC"
         /// </summary>
-        /// <remarks>8 bytes</remarks>
-        public string? Signature { get; set; }
+        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 8)]
+        public string? Signature;
 
         /// <summary>
         /// Unknown data
         /// </summary>
-        /// <remarks>5 bytes</remarks>
-        public byte[]? Unknown1 { get; set; }
+        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 5)]
+        public byte[]? Unknown1 = new byte[5];
 
         /// <summary>
         /// Version year
         /// </summary>
-        public ushort Year { get; set; }
+        public ushort Year;
 
         /// <summary>
         /// Version month
         /// </summary>
-        public byte Month { get; set; }
+        public byte Month;
 
         /// <summary>
         /// Version day
         /// </summary>
-        public byte Day { get; set; }
+        public byte Day;
 
         /// <summary>
         /// Unknown data
         /// </summary>
-        /// <remarks>4 bytes</remarks>
-        public byte[]? Unknown2 { get; set; }
+        public uint Unknown2;
 
         /// <summary>
         /// Length
         /// </summary>
-        public uint Length { get; set; }
+        public uint Length;
 
         /// <summary>
         /// Length bytes of data
diff --git a/SabreTools.Models/BSP/ColorRGBExp32.cs b/SabreTools.Models/BSP/ColorRGBExp32.cs
index a991ea0..52e8b8d 100644
--- a/SabreTools.Models/BSP/ColorRGBExp32.cs
+++ b/SabreTools.Models/BSP/ColorRGBExp32.cs
@@ -7,7 +7,7 @@ namespace SabreTools.Models.BSP
     /// </summary>
     /// <see href="https://developer.valvesoftware.com/wiki/BSP_(Source)"/> 
     [StructLayout(LayoutKind.Sequential)]
-    public struct ColorRGBExp32
+    public class ColorRGBExp32
     {
         public byte Red;
 
diff --git a/SabreTools.Models/BSP/CompressedLightCube.cs b/SabreTools.Models/BSP/CompressedLightCube.cs
index b0ab729..1fafd35 100644
--- a/SabreTools.Models/BSP/CompressedLightCube.cs
+++ b/SabreTools.Models/BSP/CompressedLightCube.cs
@@ -8,7 +8,7 @@ namespace SabreTools.Models.BSP
     /// </summary>
     /// <see href="https://developer.valvesoftware.com/wiki/BSP_(Source)"/> 
     [StructLayout(LayoutKind.Sequential)]
-    public struct CompressedLightCube
+    public class CompressedLightCube
     {
         [MarshalAs(UnmanagedType.ByValArray, SizeConst = 6)]
         public ColorRGBExp32[]? Colors;
diff --git a/SabreTools.Models/BSP/QAngle.cs b/SabreTools.Models/BSP/QAngle.cs
index b9f1b0b..985005a 100644
--- a/SabreTools.Models/BSP/QAngle.cs
+++ b/SabreTools.Models/BSP/QAngle.cs
@@ -8,7 +8,7 @@ namespace SabreTools.Models.BSP
     /// from the cardinal Z axis.
     /// </summary>
     [StructLayout(LayoutKind.Sequential)]
-    public struct QAngle
+    public class QAngle
     {
         public float X { get; set; }
         public float Y { get; set; }
diff --git a/SabreTools.Models/BSP/Vector3D.cs b/SabreTools.Models/BSP/Vector3D.cs
index 49cac66..2d5e34e 100644
--- a/SabreTools.Models/BSP/Vector3D.cs
+++ b/SabreTools.Models/BSP/Vector3D.cs
@@ -8,7 +8,7 @@ namespace SabreTools.Models.BSP
     /// spec and the code of the hlbsp project.
     /// </summary>
     [StructLayout(LayoutKind.Sequential)]
-    public struct Vector3D
+    public class Vector3D
     {
         public float X { get; set; }
         public float Y { get; set; }
diff --git a/SabreTools.Models/LinearExecutable/NonResidentNamesTableEntry.cs b/SabreTools.Models/LinearExecutable/NonResidentNamesTableEntry.cs
index f618635..aaeca40 100644
--- a/SabreTools.Models/LinearExecutable/NonResidentNamesTableEntry.cs
+++ b/SabreTools.Models/LinearExecutable/NonResidentNamesTableEntry.cs
@@ -1,4 +1,6 @@
-namespace SabreTools.Models.LinearExecutable
+using System.Runtime.InteropServices;
+
+namespace SabreTools.Models.LinearExecutable
 {
     /// <summary>
     /// The resident and non-resident name tables define the ASCII names and ordinal
@@ -25,6 +27,7 @@
     /// </summary>
     /// <see href="https://faydoc.tripod.com/formats/exe-LE.htm"/>
     /// <see href="http://www.edm2.com/index.php/LX_-_Linear_eXecutable_Module_Format_Description"/>
+    [StructLayout(LayoutKind.Sequential)]
     public sealed class NonResidentNamesTableEntry
     {
         /// <summary>
@@ -39,7 +42,7 @@
         /// signifies that additional information is contained in the linear EXE module and
         /// will be used in the future for parameter type checking.
         /// </remarks>
-        public byte Length { get; set; } // TODO: Remove in lieu of AnsiBStr
+        public byte Length { get; set; }
 
         /// <summary>
         /// ASCII String.