How to Model Smooth Models for Games with Low Poly

Question

I want to model for games.I'm using Unreal Engine for developing a game.And I have a few questions about modelling smooth looking models with low poly:

1. How many triangles supposed to be in a basic decorative model for a game which has a large map. Imagine You are modelling a mug and its just a decorative on the table and ı want to be my games graphics look nice I tried to model a cup and it took 2k-5k triangles is this too much? Subdivision Surface Modifier makes poly count very high.But without it models looks angular what am I supposed to do?

2. I wanted to make poly count lower and I tried to bake normals with a very low poly and high poly meshes.Low poly and high poly meshes was really different looking.High poly mesh was modified with Subdivision Surface Modifier twice but low poly was unmodified so when I tried to use this normal map on my low poly mesh it was looking weird(look photos for what ı mean)

3. Unreal Engine has an LOD system and when I try to make different LODs for my model with decimate modifier what I suppose to do about normal maps?Do I have to bake normal maps for every one of them.And its not just normal maps what about uv's and textures.

EDİT:After Retopolgize Edit :My expectations

Answer 1

Sometimes, depending on the model you're making, creating a high-poly version isn't always ideal and will only end up being more work.

For something like a cup you can just create a lower polygon version from the get-go. You only really need to create a high-poly version if you intend to sculpt high details or if it has a higher level of detail that you wish to bake down (things like insets, screws, etc.)

I made a video to demonstrate how I'd personally go about making this cup in order to show you that, for such an object, creating a high-poly version isn't necessary. In this video I have created this cup, using low poly modelling techniques and it is only about 700 triangles. I then show you how you can probably make it even less triangles. It still holds a nice shape, even from a distance.

At the end of the day it's all down to your own thoughts and discretion. If your model NEEDS high details then yes make a high-polygon. But if it's just the form that you're concerned with then it's not as important.

I hope this helps you. It's a bit of a long video but I really wanted to show you what I'm talking about and I hope you have a better understanding =)

The tankards, in the picture, would need a high-poly version as they have a lot of intricate details that need to be sculpted, etc. But this can also be achieved with just a texture. Your cup doesn't have those high details so a high-poly wasn't needed to begin with if that makes sense?

Video demonstration

Answer 2

I've worked with various games engines for about 18 years now so I'll try my best to answer your questions.

1. For something kinda small like that I'd say 200 tri's at the very most. 2-5k is a LOT for a cup considering that weapons tend to be about 2k max. Also creating good levels of detial (LODs) might help a lot as well but I've not really worked that much with UE4 so not sure if people even do that for this engine.

2. I suggest looking into something called retopology. You basically take your high poly model and then draw your low poly over it making sure to have good topology. It's not super important for non-animated/rigged things but it's good practice. Here's a nice tutorial that demonstrates how to do it and the add-on is free. It'll help you greatly! What software are you using for your texture work? looking into texture baking would benefit you greatly as well, AFTER watching this video. Blender 2.9 Retopology Getting Started

3. You won't have to remake textures and normal maps for the LOD's as the LOD's use the texture information of the model itself and, let's face it, from a distance you can't really see normal maps anyway.

If you need further help just ask ^.^