Hi all I'm new to mapping so I have many questions to ask so i opened this thread. Please explain as much as you can. Thanks in advance. Problems not solved are underlined. 1. How does occluder work? I know what visleaf,hint, areaportal and func_detail well so feel free to explain. 2. I know that we can make a sphere by either displacement or normal brush. Which is more costly? 3. Is decompiling models the only way to flip or resize models? 4. I want to make a payload map in which players are trying to push the cart as much as possible. The track is an endless loop so that laps pushed by players determines which team wins. My question is how to set up the team_train_watcher entity, as it doesn't have the ending node? 5. I find that player models created by prop_dynamic are so costly. How can we reduce the cost of them? 6. How can the map determine whether a player is killed by sawblade, train or any other objects? 7. What is the maximum number of control points and flags I can create in a single stage in a single map? 8. What is the largest brush I can create in game without errors? 9. When 2 different brushes are on the same plane, The VVIS still split the visleaf in that area. Is it a glitch or what? 10. After I placed clip on metal stairs, walking on it won't produced the sound when you walk on a metal surface. Can it be fixed? 11. After I enlarge a decal, It becomes weird in hammer and also in game. Why does this happened? 12. At most how many switchable lights can shine on a surface simultaneously? 13. How can I indicate an area by placing a glowing brush which isn't a solid? Thanks!!