How to fix those texture errors?

NAIMA

I get often those issues, even if the uvmap is perfectly clear, , the lp model is perfectly matching the high poly one , so I do not understand why I get those artefacts?

poopipe

projection distances are too high 

NAIMA

are set to 0.01 , what should I put it like?

poopipe

it depends how large your object is and how large the parts causing the issues are in relation to it

do a load of test bakes with different values and eventually you'll find one that works 

gnoop

That's why I often prefer to bake world/object space normal map  as exr    and then re-bake/turn it to  tangent space one.     No pain with cages or distances and usually super quick to render.    Works well for floating  geo  sharing same UV space.    

You can use Blender /Cycles  or Substance Designer baker  for conversion.   Bet it should work  with any renderer actually.  Did it in Modo years ago too.

The only condition is your Low and high should share same UV that is often a case  when you start detailing  from unwrapped Low or produce your high by bevel/chamfer modifiers.

poopipe

That's certainly an option but I'd suggest its an approach that requires a deeper understanding of the process than the original question indicates the OP posesses. 

There's absolutely no reason why the part of the object pictured can't be baked to tangent space with no cage.
The OP just needs to read the instructions and  try a few different numbers until it looks right. 

If the object is a weird shape (eg. very long in one axis) OP might do better to disable the relative to bounding volume option and instead work in world space units 

gnoop

For such a pretty "mid res" object  it's definitely wouldn't be an issue  to find distance after few tries.    But since I often bake for lod02 and extremely low poly geo,  sometimes  grouped things into some kind of boxy shell  with only silhouette having more or less enough vertexes  that distance slider sometimes doesn't work.    Like a short blanket . 

You do it right for one part of an object   with  smaller details  and in other part  where it's less visually important and having just a few vertexes  the surface is so angular and boxy    the distance  set too short  makes  hi res protrusions .    

The way I described  could be  a cage replacement  in such cases  and  while in some soft it's a headache to figure out proper axis positions   in Blender it's as simple as at first baking object space exr for hires object, applying it in the shader as object space normal map  on low res counterpart  and bake tangent space from it  without hi res  involved.

In SD you could do same only with local Y up  object space baked.