diff --git a/vtm/src/org/oscim/renderer/BufferObject.java b/vtm/src/org/oscim/renderer/BufferObject.java
index 0d51a86f..b89be05e 100644
--- a/vtm/src/org/oscim/renderer/BufferObject.java
+++ b/vtm/src/org/oscim/renderer/BufferObject.java
@@ -24,22 +24,23 @@ import org.oscim.backend.Log;
 
 public final class BufferObject {
 	private final static String TAG = BufferObject.class.getName();
-
-	private static GL20 GL;
-
 	private static final int MB = 1024 * 1024;
 	private static final int LIMIT_BUFFERS = 16 * MB;
 
-	// GL identifier
-	public int id;
-	// allocated bytes
-	public int size;
+	private static GL20 GL;
 
-	BufferObject next;
+	/** GL identifier */
+	private int id;
 
-	int target;
+	/** allocated bytes */
+	private int size;
 
-	BufferObject(int target, int id) {
+	/** GL_ARRAY_BUFFER or GL_ELEMENT_ARRAY_BUFFER */
+	private int target;
+
+	private BufferObject next;
+
+	private BufferObject(int target, int id) {
 		this.id = id;
 		this.target = target;
 	}
@@ -47,9 +48,10 @@ public final class BufferObject {
 	public void loadBufferData(Buffer buf, int newSize) {
 		boolean clear = false;
 
-		if (buf.position() != 0) {
-			Log.d(TAG, "rewind your buffer: " + buf.position());
-		}
+		if (buf.position() != 0)
+			buf.flip();
+
+		//throw new IllegalArgumentException("rewind buffer! " + buf.position());
 
 		GL.glBindBuffer(target, id);
 
@@ -68,6 +70,10 @@ public final class BufferObject {
 		GL.glBindBuffer(target, id);
 	}
 
+	public void unbind() {
+		GL.glBindBuffer(target, 0);
+	}
+
 	// ---------------------------- pool ----------------------------
 	// bytes currently loaded in VBOs
 	private static int mBufferMemoryUsage;
@@ -77,9 +83,7 @@ public final class BufferObject {
 		if (mBufferMemoryUsage < LIMIT_BUFFERS)
 			return;
 
-		Log.d(TAG, "buffer object usage: "
-		        + mBufferMemoryUsage / MB
-		        + "MB, force: " + force);
+		Log.d(TAG, "use: " + mBufferMemoryUsage / MB + "MB");
 
 		mBufferMemoryUsage -= BufferObject.limitUsage(1024 * 1024);
 
diff --git a/vtm/src/org/oscim/renderer/ElementRenderer.java b/vtm/src/org/oscim/renderer/ElementRenderer.java
index 5cab5e4f..c94d0ae3 100644
--- a/vtm/src/org/oscim/renderer/ElementRenderer.java
+++ b/vtm/src/org/oscim/renderer/ElementRenderer.java
@@ -153,9 +153,8 @@ public abstract class ElementRenderer extends LayerRenderer {
 			sbuf.put(fillCoords, 0, 8);
 
 		layers.compile(sbuf, addFill);
-		sbuf.flip();
 
-		if (newSize != sbuf.remaining()) {
+		if (newSize != sbuf.position()) {
 			Log.d(TAG, "wrong size: "
 			        + " new size: " + newSize
 			        + " buffer pos: " + sbuf.position()
@@ -164,10 +163,7 @@ public abstract class ElementRenderer extends LayerRenderer {
 			return false;
 		}
 
-		// * SHORT_BYTES
-		newSize *= 2;
-
-		layers.vbo.loadBufferData(sbuf, newSize);
+		layers.vbo.loadBufferData(sbuf.flip(), newSize * 2);
 		return true;
 	}
 
diff --git a/vtm/src/org/oscim/renderer/elements/ExtrusionLayer.java b/vtm/src/org/oscim/renderer/elements/ExtrusionLayer.java
index c3903a97..6ce577c0 100644
--- a/vtm/src/org/oscim/renderer/elements/ExtrusionLayer.java
+++ b/vtm/src/org/oscim/renderer/elements/ExtrusionLayer.java
@@ -378,10 +378,9 @@ public class ExtrusionLayer extends RenderElement {
 			mNumIndices += mIndiceCnt[i];
 		}
 
-		sbuf.flip();
 		int size = mNumIndices * 2;
 		vboIndices = BufferObject.get(GL20.GL_ELEMENT_ARRAY_BUFFER, size);
-		vboIndices.loadBufferData(sbuf, size);
+		vboIndices.loadBufferData(sbuf.flip(), size);
 
 		GL20 GL = GLAdapter.get();
 		GL.glBindBuffer(GL20.GL_ELEMENT_ARRAY_BUFFER, 0);
@@ -391,10 +390,9 @@ public class ExtrusionLayer extends RenderElement {
 		for (VertexItem vi = mVertices; vi != null; vi = vi.next)
 			sbuf.put(vi.vertices, 0, vi.used);
 
-		sbuf.flip();
 		size = mNumVertices * 4 * 2;
 		vboVertices = BufferObject.get(GL20.GL_ARRAY_BUFFER, size);
-		vboVertices.loadBufferData(sbuf, size);
+		vboVertices.loadBufferData(sbuf.flip(), size);
 
 		GL.glBindBuffer(GL20.GL_ARRAY_BUFFER, 0);
 
diff --git a/vtm/src/org/oscim/renderer/elements/MeshLayer.java b/vtm/src/org/oscim/renderer/elements/MeshLayer.java
index 1d367512..10b9f8ea 100644
--- a/vtm/src/org/oscim/renderer/elements/MeshLayer.java
+++ b/vtm/src/org/oscim/renderer/elements/MeshLayer.java
@@ -59,7 +59,7 @@ public class MeshLayer extends RenderElement {
 
 		verticesCnt = vertexItems.getSize() / 2;
 
-		Log.d(TAG, "-> " + verticesCnt + " " + numIndices);
+		//Log.d(TAG, "-> " + verticesCnt + " " + numIndices);
 
 		if (numIndices <= 0) {
 			vertexItems = VertexItem.pool.releaseAll(vertexItems);
@@ -74,13 +74,13 @@ public class MeshLayer extends RenderElement {
 			return;
 		}
 
-		Log.d(TAG, "compile");
+		//Log.d(TAG, "compile");
 		// add vertices to shared VBO
 		ElementLayers.addPoolItems(this, sbuf);
 
 		int cnt = indiceItems.getSize();
 
-		Log.d(TAG, "check " + cnt + ":" + numIndices);
+		//Log.d(TAG, "check " + cnt + ":" + numIndices);
 
 		if (cnt != numIndices) {
 			numIndices = cnt;
@@ -94,12 +94,10 @@ public class MeshLayer extends RenderElement {
 
 		indiceItems = VertexItem.pool.releaseAll(indiceItems);
 
-		sbuf.flip();
-
 		if (indicesVbo == null)
 			indicesVbo = BufferObject.get(GL20.GL_ELEMENT_ARRAY_BUFFER, 0);
 
-		indicesVbo.loadBufferData(sbuf, sbuf.limit() * 2);
+		indicesVbo.loadBufferData(sbuf.flip(), sbuf.limit() * 2);
 	}
 
 	@Override
diff --git a/vtm/src/org/oscim/renderer/test/CustomRenderer2.java b/vtm/src/org/oscim/renderer/test/CustomRenderer2.java
index f9616c93..37125fb3 100644
--- a/vtm/src/org/oscim/renderer/test/CustomRenderer2.java
+++ b/vtm/src/org/oscim/renderer/test/CustomRenderer2.java
@@ -82,10 +82,9 @@ public class CustomRenderer2 extends ElementRenderer {
 		}
 		FloatBuffer buf = MapRenderer.getFloatBuffer(12);
 		buf.put(vertices);
-		buf.flip();
 
 		mVBO = BufferObject.get(GL20.GL_ARRAY_BUFFER, 0);
-		mVBO.loadBufferData(buf, 12 * 4);
+		mVBO.loadBufferData(buf.flip(), 12 * 4);
 
 		setReady(true);
 	}