is there an advantage if your object is in one mesh?

recently, i looked at the andrew price’s jerry can video, and then downloaded the jerry can, and then realized that the jerry can, though 1 object is made from the body, can, and handel, which made me thinking, why do i always try to make one object in one mesh?
like the last time, i tried to make a cathedral temple (full scale) FROM one mesh; is there an advantage, because i know the disadvantages of not being able to make ALOT of things. so if it’s bad, i’ll stop
so is it bad?

Constricting yourself to one mesh is only making it harder for yourself to edit it later. By separating it into several objects you can isolate the ones you are working on, use modifiers on specific parts of your mesh and so on.

I would suggest making a cathedral (for example) as multiple objects.

Moved from “General Forums > Blender and CG Discussions” to “Support > Basics & Interface”

@1832vin, you’ve been warned multiple times before. Please do not post support questions in the general forums.

As to your question, the simple answer is that it depends. If it’s for a single static still image, it really doesn’t matter at all. If you’re 3D printing the model, it’s much more important. If you’re working with a character that’s meant to be rigged and animated, the answer is much less clear.

The only situation in which a model must be a single watertight manifold mesh is if you wish to 3d print it. Otherwise it is very normal to make the model from many separate objects either touching each other or intersecting. If the parts of an object can move relative to each other (like the turret on a tank, or the legs on a mech, or the wheels on a car) then the moving parts should be separate onjects parented to the main body object, if the parts all stay stationary relative to each other(like the superstructure of a ship relative to it’s hull, or muzzle of a gun relative to it’s breach, or the roof of a building relative to it’s walls) then it is best to make them separetly but then join their meshes together into one object, although this object need not be manifold or watertight, it’s just an easy way to keep all the parts together without adding extra objects which might make animating your scene more tricky.

Especially for your cathedral, make each column separetely, each arch separately then copy them along to make the nave. Make each piece of the roof separately, and the lead or slate outside of the roof as a separate object to the lovely gothic internal vault . Copy this along. Make a few different types of gargoyle as separate objects then copy them and place them in the correct niches and alcoves. It is no problem if these objects have faces which intersect each other. At the end select all the separate objects and join them into one object, unless you want to animate it being built or collapsing, in which case make each beam, column, arch and stone a separate object which can be individually animated. making the whole cathedral as one watertight object would be harmless (except for the small risk of leading to bad geometry that would render to give annoying little black triangles on some of the faces) but it would be unneccessary effort compared to making the parts separately. Also an advantage of having separate intersecting parts is that texturing can be easier, imagine a wall with columns built onto it, if you modelled it in a watertight solid way then it would be one manifold mesh with a fac for the wall, then some faces curving round for the column, then another face for the next piece of wall, then another column. Each wall face would need to have a texture positioned onto it. If on the other hand you modelled a single flat face for the wall and had it intersected by other objects (the columns) at intervals then you could position the texture for the wall just once on the one big face.

Regarding 3d printing, if you are making this model to be 3d printed then make it a simple low poly structure, 3d printers don’t cope well with the extremely fine details you will find on a full 3d model of the building which is designed for rendering,animating or games. I would assume given that cathedrals are usually very intricate structures with thousands of tiny details (look at the old gothic buildings and you see little figures, levaes and faces carved on more or less every surface) you are modelling thit to render and animate, not to print. If you were printing it then modelling as a single solid object would be crucial.

Up to you and what the scene/model has going for it. Separate is better while editing because it gives you a clear idea what you’re looking at (mesh/object data/uvs) Also your select A in edit more is more reliable (fast) when it is only grabbing small parts of the scene and not everything.

Something useful: L key in edit mode can select multiple different objects from the same edit mode. Example: Add a 2nd cube while still inside the 1st cubes edit mode. Deselect both cubes, hover mouse over a vert/edge/face and press L. Limited select all. Very useful. I’d recommend going into the user prefs and changing the L key bind in edit mode to Q instead. (:

For instance this room is made up of 330 different objects/edit modes. Doing all this from 1 primitive would be expensive and really messy. Messy is no fun to work with when it comes to materials. Think how they would make the room in real life. The walls, floors and ceiling should likely all be one tight mesh. Then inside there are many different props people had to bring and set down there.

Remember you can separate and join as much as you want in the process.