Currently there are several different properties that control where project output goes. If you want all project output for a repo to go under a single folder, it is certainly possible to set this up, but it involves setting several properties, and knowing how to include $(MSBuildProjectName) as part of the path. For example, you can put the following in a Directory.Build.props file (assuming all your projects use Microsoft.NET.Sdk):

<RepoRoot>$([System.IO.Path]::GetFullPath('$(MSBuildThisFileDirectory)'))</RepoRoot>
<BaseOutputPath>$(RepoRoot)artifacts\bin\$(MSBuildProjectName)\</BaseOutputPath>
<BaseIntermediateOutputPath>$(RepoRoot)artifacts\obj\$(MSBuildProjectName)\</BaseIntermediateOutputPath>

We would like to add a single property (for example RootOutputPath) that handles this automatically.

See also dotnet/sdk#867