diff --git a/d2common/d2fileformats/d2ds1/ds1.go b/d2common/d2fileformats/d2ds1/ds1.go
index fd9ecf40..5d809c9e 100644
--- a/d2common/d2fileformats/d2ds1/ds1.go
+++ b/d2common/d2fileformats/d2ds1/ds1.go
@@ -30,7 +30,7 @@ type DS1 struct {
 	*ds1Layers
 	Files              []string            // FilePtr table of file string pointers
 	Objects            []Object            // Objects
-	substitutionGroups []SubstitutionGroup // Substitution groups for the DS1
+	SubstitutionGroups []SubstitutionGroup // Substitution groups for the DS1
 
 	version          ds1version
 	Act              int32 // Act, from 1 to 5. This tells which Act table to use for the Objects list
@@ -111,7 +111,7 @@ func (ds1 *DS1) loadHeader(br *d2datautils.StreamReader) error {
 
 		switch ds1.SubstitutionType {
 		case subType1, subType2:
-			ds1.PushSubstitution(&layer{})
+			ds1.PushSubstitution(&Layer{})
 		}
 	}
 
@@ -158,19 +158,19 @@ func (ds1 *DS1) loadBody(stream *d2datautils.StreamReader) error {
 	}
 
 	for ; numWalls > 0; numWalls-- {
-		ds1.PushWall(&layer{})
+		ds1.PushWall(&Layer{})
 	}
 
 	for ; numShadows > 0; numShadows-- {
-		ds1.PushShadow(&layer{})
+		ds1.PushShadow(&Layer{})
 	}
 
 	for ; numFloors > 0; numFloors-- {
-		ds1.PushFloor(&layer{})
+		ds1.PushFloor(&Layer{})
 	}
 
 	for ; numSubstitutions > 0; numSubstitutions-- {
-		ds1.PushSubstitution(&layer{})
+		ds1.PushSubstitution(&Layer{})
 	}
 
 	ds1.SetSize(ds1.width, ds1.height)
@@ -287,7 +287,7 @@ func (ds1 *DS1) loadSubstitutions(br *d2datautils.StreamReader) error {
 		(ds1.SubstitutionType == subType1 || ds1.SubstitutionType == subType2)
 
 	if !hasSubstitutions {
-		ds1.substitutionGroups = make([]SubstitutionGroup, 0)
+		ds1.SubstitutionGroups = make([]SubstitutionGroup, 0)
 		return nil
 	}
 
@@ -303,7 +303,7 @@ func (ds1 *DS1) loadSubstitutions(br *d2datautils.StreamReader) error {
 		return fmt.Errorf("reading number of sub groups: %w", err)
 	}
 
-	ds1.substitutionGroups = make([]SubstitutionGroup, numberOfSubGroups)
+	ds1.SubstitutionGroups = make([]SubstitutionGroup, numberOfSubGroups)
 
 	for subIdx := 0; subIdx < int(numberOfSubGroups); subIdx++ {
 		newSub := SubstitutionGroup{}
@@ -333,7 +333,7 @@ func (ds1 *DS1) loadSubstitutions(br *d2datautils.StreamReader) error {
 			return fmt.Errorf("reading substitution's %d unknown: %v", subIdx, err)
 		}
 
-		ds1.substitutionGroups[subIdx] = newSub
+		ds1.SubstitutionGroups[subIdx] = newSub
 	}
 
 	return err
@@ -599,9 +599,9 @@ func (ds1 *DS1) Marshal() []byte {
 	if hasSubstitutions {
 		sw.PushUint32(ds1.unknown2)
 
-		sw.PushUint32(uint32(len(ds1.substitutionGroups)))
+		sw.PushUint32(uint32(len(ds1.SubstitutionGroups)))
 
-		for _, i := range ds1.substitutionGroups {
+		for _, i := range ds1.SubstitutionGroups {
 			sw.PushInt32(i.TileX)
 			sw.PushInt32(i.TileY)
 			sw.PushInt32(i.WidthInTiles)
diff --git a/d2common/d2fileformats/d2ds1/ds1_layers.go b/d2common/d2fileformats/d2ds1/ds1_layers.go
index b1ea93ee..65636c95 100644
--- a/d2common/d2fileformats/d2ds1/ds1_layers.go
+++ b/d2common/d2fileformats/d2ds1/ds1_layers.go
@@ -16,7 +16,7 @@ const (
 	substitutionLayerGroup
 )
 
-type layerGroup []*layer
+type layerGroup []*Layer
 
 type ds1Layers struct {
 	width, height int
@@ -123,9 +123,10 @@ func (l *ds1Layers) SetHeight(h int) {
 }
 
 // generic push func for all layer types
-func (l *ds1Layers) push(t layerGroupType, layer *layer) {
+func (l *ds1Layers) push(t layerGroupType, layer *Layer) {
 	l.ensureInit()
 	l.cull()
+	layer.SetSize(l.Size())
 
 	group := l.getLayersGroup(t)
 
@@ -137,7 +138,7 @@ func (l *ds1Layers) push(t layerGroupType, layer *layer) {
 }
 
 // generic pop func for all layer types
-func (l *ds1Layers) pop(t layerGroupType) *layer {
+func (l *ds1Layers) pop(t layerGroupType) *Layer {
 	l.ensureInit()
 	l.cull()
 
@@ -146,7 +147,7 @@ func (l *ds1Layers) pop(t layerGroupType) *layer {
 		return nil
 	}
 
-	var theLayer *layer
+	var theLayer *Layer
 
 	// remove last layer of slice and return it
 	if len(*group) > 0 {
@@ -160,7 +161,7 @@ func (l *ds1Layers) pop(t layerGroupType) *layer {
 	return nil
 }
 
-func (l *ds1Layers) get(t layerGroupType, idx int) *layer {
+func (l *ds1Layers) get(t layerGroupType, idx int) *Layer {
 	l.ensureInit()
 	l.cull()
 
@@ -176,7 +177,7 @@ func (l *ds1Layers) get(t layerGroupType, idx int) *layer {
 	return (*group)[idx]
 }
 
-func (l *ds1Layers) insert(t layerGroupType, idx int, newLayer *layer) {
+func (l *ds1Layers) insert(t layerGroupType, idx int, newLayer *Layer) {
 	l.ensureInit()
 	l.cull()
 
@@ -184,6 +185,8 @@ func (l *ds1Layers) insert(t layerGroupType, idx int, newLayer *layer) {
 		return
 	}
 
+	newLayer.SetSize(l.Size())
+
 	group := l.getLayersGroup(t)
 	if group == nil {
 		return
@@ -207,7 +210,7 @@ func (l *ds1Layers) insert(t layerGroupType, idx int, newLayer *layer) {
 	//		idx=1
 	//		newLayer=c
 	// 		existing layerGroup is [a, b]
-	newGroup := append((*group)[:idx], append([]*layer{newLayer}, (*group)[idx:]...)...)
+	newGroup := append((*group)[:idx], append([]*Layer{newLayer}, (*group)[idx:]...)...)
 	*group = newGroup
 }
 
@@ -229,20 +232,20 @@ func (l *ds1Layers) delete(t layerGroupType, idx int) {
 	l.cull()
 }
 
-func (l *ds1Layers) GetFloor(idx int) *layer {
+func (l *ds1Layers) GetFloor(idx int) *Layer {
 	return l.get(floorLayerGroup, idx)
 }
 
-func (l *ds1Layers) PushFloor(floor *layer) *ds1Layers {
+func (l *ds1Layers) PushFloor(floor *Layer) *ds1Layers {
 	l.push(floorLayerGroup, floor)
 	return l
 }
 
-func (l *ds1Layers) PopFloor() *layer {
+func (l *ds1Layers) PopFloor() *Layer {
 	return l.pop(floorLayerGroup)
 }
 
-func (l *ds1Layers) InsertFloor(idx int, newFloor *layer) {
+func (l *ds1Layers) InsertFloor(idx int, newFloor *Layer) {
 	l.insert(floorLayerGroup, idx, newFloor)
 }
 
@@ -250,20 +253,20 @@ func (l *ds1Layers) DeleteFloor(idx int) {
 	l.delete(floorLayerGroup, idx)
 }
 
-func (l *ds1Layers) GetWall(idx int) *layer {
+func (l *ds1Layers) GetWall(idx int) *Layer {
 	return l.get(wallLayerGroup, idx)
 }
 
-func (l *ds1Layers) PushWall(wall *layer) *ds1Layers {
+func (l *ds1Layers) PushWall(wall *Layer) *ds1Layers {
 	l.push(wallLayerGroup, wall)
 	return l
 }
 
-func (l *ds1Layers) PopWall() *layer {
+func (l *ds1Layers) PopWall() *Layer {
 	return l.pop(wallLayerGroup)
 }
 
-func (l *ds1Layers) InsertWall(idx int, newWall *layer) {
+func (l *ds1Layers) InsertWall(idx int, newWall *Layer) {
 	l.insert(wallLayerGroup, idx, newWall)
 }
 
@@ -271,20 +274,20 @@ func (l *ds1Layers) DeleteWall(idx int) {
 	l.delete(wallLayerGroup, idx)
 }
 
-func (l *ds1Layers) GetShadow(idx int) *layer {
+func (l *ds1Layers) GetShadow(idx int) *Layer {
 	return l.get(shadowLayerGroup, idx)
 }
 
-func (l *ds1Layers) PushShadow(shadow *layer) *ds1Layers {
+func (l *ds1Layers) PushShadow(shadow *Layer) *ds1Layers {
 	l.push(shadowLayerGroup, shadow)
 	return l
 }
 
-func (l *ds1Layers) PopShadow() *layer {
+func (l *ds1Layers) PopShadow() *Layer {
 	return l.pop(shadowLayerGroup)
 }
 
-func (l *ds1Layers) InsertShadow(idx int, newShadow *layer) {
+func (l *ds1Layers) InsertShadow(idx int, newShadow *Layer) {
 	l.insert(shadowLayerGroup, idx, newShadow)
 }
 
@@ -292,20 +295,20 @@ func (l *ds1Layers) DeleteShadow(idx int) {
 	l.delete(shadowLayerGroup, idx)
 }
 
-func (l *ds1Layers) GetSubstitution(idx int) *layer {
+func (l *ds1Layers) GetSubstitution(idx int) *Layer {
 	return l.get(substitutionLayerGroup, idx)
 }
 
-func (l *ds1Layers) PushSubstitution(sub *layer) *ds1Layers {
+func (l *ds1Layers) PushSubstitution(sub *Layer) *ds1Layers {
 	l.push(substitutionLayerGroup, sub)
 	return l
 }
 
-func (l *ds1Layers) PopSubstitution() *layer {
+func (l *ds1Layers) PopSubstitution() *Layer {
 	return l.pop(substitutionLayerGroup)
 }
 
-func (l *ds1Layers) InsertSubstitution(idx int, newSubstitution *layer) {
+func (l *ds1Layers) InsertSubstitution(idx int, newSubstitution *Layer) {
 	l.insert(substitutionLayerGroup, idx, newSubstitution)
 }
 
diff --git a/d2common/d2fileformats/d2ds1/ds1_layers_test.go b/d2common/d2fileformats/d2ds1/ds1_layers_test.go
index 62a139da..47bfe127 100644
--- a/d2common/d2fileformats/d2ds1/ds1_layers_test.go
+++ b/d2common/d2fileformats/d2ds1/ds1_layers_test.go
@@ -74,17 +74,17 @@ func Test_ds1Layers_Get(t *testing.T) {
 func ds1LayersGet(t *testing.T, lt layerGroupType) {
 	ds1 := exampleData()
 
-	var get func(i int) *layer
+	var get func(i int) *Layer
 
 	switch lt {
 	case floorLayerGroup:
-		get = func(i int) *layer { return ds1.GetFloor(0) }
+		get = func(i int) *Layer { return ds1.GetFloor(0) }
 	case wallLayerGroup:
-		get = func(i int) *layer { return ds1.GetWall(0) }
+		get = func(i int) *Layer { return ds1.GetWall(0) }
 	case shadowLayerGroup:
-		get = func(i int) *layer { return ds1.GetShadow(0) }
+		get = func(i int) *Layer { return ds1.GetShadow(0) }
 	case substitutionLayerGroup:
-		get = func(i int) *layer { return ds1.GetSubstitution(0) }
+		get = func(i int) *Layer { return ds1.GetSubstitution(0) }
 	default:
 		t.Fatal("unknown layer type given")
 		return
@@ -116,11 +116,11 @@ func Test_ds1Layers_Insert(t *testing.T) {
 func ds1LayersInsert(t *testing.T, lt layerGroupType) {
 	ds1 := DS1{}
 
-	layers := make([]*layer, getMaxGroupLen(lt)+1)
+	layers := make([]*Layer, getMaxGroupLen(lt)+1)
 
 	for i := range layers {
 		i := i
-		layers[i] = &layer{}
+		layers[i] = &Layer{}
 		layers[i].tiles = make(tileGrid, 1)
 		layers[i].tiles[0] = make(tileRow, 1)
 		layers[i].SetSize(3, 3)
@@ -184,14 +184,14 @@ func Test_ds1Layers_Pop(t *testing.T) {
 func ds1layerPop(lt layerGroupType, t *testing.T) {
 	ds1 := exampleData()
 
-	var pop func() *layer
+	var pop func() *Layer
 
 	var numBefore, numAfter int
 
 	switch lt {
 	case floorLayerGroup:
 		numBefore = len(ds1.Floors)
-		pop = func() *layer {
+		pop = func() *Layer {
 			l := ds1.PopFloor()
 			numAfter = len(ds1.Floors)
 
@@ -199,7 +199,7 @@ func ds1layerPop(lt layerGroupType, t *testing.T) {
 		}
 	case wallLayerGroup:
 		numBefore = len(ds1.Walls)
-		pop = func() *layer {
+		pop = func() *Layer {
 			l := ds1.PopWall()
 			numAfter = len(ds1.Walls)
 
@@ -207,7 +207,7 @@ func ds1layerPop(lt layerGroupType, t *testing.T) {
 		}
 	case shadowLayerGroup:
 		numBefore = len(ds1.Shadows)
-		pop = func() *layer {
+		pop = func() *Layer {
 			l := ds1.PopShadow()
 			numAfter = len(ds1.Shadows)
 
@@ -215,7 +215,7 @@ func ds1layerPop(lt layerGroupType, t *testing.T) {
 		}
 	case substitutionLayerGroup:
 		numBefore = len(ds1.Substitutions)
-		pop = func() *layer {
+		pop = func() *Layer {
 			l := ds1.PopSubstitution()
 			numAfter = len(ds1.Substitutions)
 
@@ -271,7 +271,7 @@ func ds1layerPush(lt layerGroupType, t *testing.T) { //nolint:funlen // no biggi
 	// we need to set up some shit to handle the test in a generic way
 	var push func()
 
-	var get func(idx int) *layer
+	var get func(idx int) *Layer
 
 	var max int
 
@@ -292,22 +292,22 @@ func ds1layerPush(lt layerGroupType, t *testing.T) { //nolint:funlen // no biggi
 
 	switch lt {
 	case floorLayerGroup:
-		push = func() { layers.PushFloor(&layer{}) }
+		push = func() { layers.PushFloor(&Layer{}) }
 		get = layers.GetFloor
 		max = maxFloorLayers
 		group = &layers.Floors
 	case wallLayerGroup:
-		push = func() { layers.PushWall(&layer{}) }
+		push = func() { layers.PushWall(&Layer{}) }
 		get = layers.GetWall
 		max = maxWallLayers
 		group = &layers.Walls
 	case shadowLayerGroup:
-		push = func() { layers.PushShadow(&layer{}) }
+		push = func() { layers.PushShadow(&Layer{}) }
 		get = layers.GetShadow
 		max = maxShadowLayers
 		group = &layers.Shadows
 	case substitutionLayerGroup:
-		push = func() { layers.PushSubstitution(&layer{}) }
+		push = func() { layers.PushSubstitution(&Layer{}) }
 		get = layers.GetSubstitution
 		max = maxSubstitutionLayers
 		group = &layers.Substitutions
diff --git a/d2common/d2fileformats/d2ds1/ds1_test.go b/d2common/d2fileformats/d2ds1/ds1_test.go
index 2ba80a0a..27738e49 100644
--- a/d2common/d2fileformats/d2ds1/ds1_test.go
+++ b/d2common/d2fileformats/d2ds1/ds1_test.go
@@ -174,7 +174,7 @@ func exampleData() *DS1 { //nolint:funlen // not a big deal if this is long func
 			{0, 2, 0, 0, 0, nil},
 			{0, 3, 0, 0, 0, nil},
 		},
-		substitutionGroups: nil,
+		SubstitutionGroups: nil,
 		version:            17,
 		Act:                1,
 		SubstitutionType:   0,
diff --git a/d2common/d2fileformats/d2ds1/layer.go b/d2common/d2fileformats/d2ds1/layer.go
index d77b86fd..64edbe9a 100644
--- a/d2common/d2fileformats/d2ds1/layer.go
+++ b/d2common/d2fileformats/d2ds1/layer.go
@@ -19,14 +19,18 @@ const (
 	layerStreamSubstitute1
 )
 
-type tileRow []Tile     // index is x coordinate
-type tileGrid []tileRow // index is y coordinate
+type (
+	tileRow  []Tile    // index is x coordinate
+	tileGrid []tileRow // index is y coordinate
+)
 
-type layer struct {
+// Layer is an abstraction of a tile grid with some helper methods
+type Layer struct {
 	tiles tileGrid
 }
 
-func (l *layer) Tile(x, y int) *Tile {
+// Tile returns the tile at the given x,y coordinate in the grid, or nil if empty.
+func (l *Layer) Tile(x, y int) *Tile {
 	if l.Width() < x || l.Height() < y {
 		return nil
 	}
@@ -34,7 +38,8 @@ func (l *layer) Tile(x, y int) *Tile {
 	return &l.tiles[y][x]
 }
 
-func (l *layer) SetTile(x, y int, t *Tile) {
+// SetTile sets the tile at the given x,y coordinate in the tile grid
+func (l *Layer) SetTile(x, y int, t *Tile) {
 	if l.Width() > x || l.Height() > y {
 		return
 	}
@@ -42,7 +47,8 @@ func (l *layer) SetTile(x, y int, t *Tile) {
 	l.tiles[y][x] = *t
 }
 
-func (l *layer) Width() int {
+// Width returns the width of the tile grid
+func (l *Layer) Width() int {
 	if len(l.tiles[0]) < 1 {
 		l.SetWidth(1)
 	}
@@ -50,7 +56,8 @@ func (l *layer) Width() int {
 	return len(l.tiles[0])
 }
 
-func (l *layer) SetWidth(w int) *layer {
+// SetWidth sets the width of the tile grid, minimum of 1
+func (l *Layer) SetWidth(w int) *Layer {
 	if w < 1 {
 		w = 1
 	}
@@ -80,7 +87,8 @@ func (l *layer) SetWidth(w int) *layer {
 	return l
 }
 
-func (l *layer) Height() int {
+// Height returns the height of the tile grid
+func (l *Layer) Height() int {
 	if len(l.tiles) < 1 {
 		l.SetHeight(1)
 	}
@@ -88,7 +96,8 @@ func (l *layer) Height() int {
 	return len(l.tiles)
 }
 
-func (l *layer) SetHeight(h int) *layer {
+// SetHeight sets the height of the tile grid, minimum of 1
+func (l *Layer) SetHeight(h int) *Layer {
 	if h < 1 {
 		h = 1
 	}
@@ -120,10 +129,12 @@ func (l *layer) SetHeight(h int) *layer {
 	return l
 }
 
-func (l *layer) Size() (w, h int) {
+// Size returns the width and height of the tile grid
+func (l *Layer) Size() (w, h int) {
 	return l.Width(), l.Height()
 }
 
-func (l *layer) SetSize(w, h int) *layer {
+// SetSize sets the width and height of the tile grid
+func (l *Layer) SetSize(w, h int) *Layer {
 	return l.SetWidth(w).SetHeight(h)
 }
diff --git a/d2common/d2fileformats/d2ds1/layer_test.go b/d2common/d2fileformats/d2ds1/layer_test.go
index 92c37ea6..055c2056 100644
--- a/d2common/d2fileformats/d2ds1/layer_test.go
+++ b/d2common/d2fileformats/d2ds1/layer_test.go
@@ -7,7 +7,7 @@ func Test_layers(t *testing.T) {
 		fmtWidthHeightError = "unexpected wall layer width/height: %dx%d"
 	)
 
-	l := &layer{}
+	l := &Layer{}
 
 	l.SetSize(0, 0)