# Defining predetermined values on surface of domain

**URL:** <https://discourse.julialang.org/t/defining-predetermined-values-on-surface-of-domain/105799>\
**Category:** New to Julia\
**Tags:** question, gridap\
**Created:** [November 4, 2023, 6:47pm UTC](https://discourse.julialang.org/t/defining-predetermined-values-on-surface-of-domain/105799 "2023-11-04T18:47:23Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![mary](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mary/32/53139_2.png) [@mary](https://discourse.julialang.org/u/mary)\
**Post date:** [November 4, 2023, 6:47pm UTC](https://discourse.julialang.org/t/defining-predetermined-values-on-surface-of-domain/105799/1 "2023-11-04T18:47:23Z")

</div>

Hi, I am using gridap to evaluate 3 different variables density, displacement and phase field. my domain is a rectangle and there are 3 small rectangles around supports and load that i want to assign value of 1 to those areas and do not entering these areas in calculations. i used tags for nodes and line for defining supports but i cant make it for surface. can you help me how can i di this?

```julia
order = 1
reffe_PF = ReferenceFE(lagrangian ,Float64,order)
V0_PF = TestFESpace(model ,reffe_PF;conformity =:H1,
    dirichlet_tags = ["LeftSupport","RightSupport", "LoadLine"],
    dirichlet_masks =[true,true,true])
order = 1
reffe_Disp = ReferenceFE(lagrangian ,VectorValue{2,Float64},order)
V0_Disp = TestFESpace(model,reffe_Disp;conformity =:H1,
    dirichlet_tags = ["LeftSupport","RightSupport", "LoadLine"],
    dirichlet_masks =[(false ,true), (true ,true), (false ,true)])
degree = 2*order
Ω= Triangulation(model)
dΩ= Measure(Ω,degree)
p_reffe = ReferenceFE(lagrangian, Float64, 0)
Q = TestFESpace(Ω, p_reffe, vector_type = Vector{Float64},
    dirichlet_tags = ["LeftSupport","RightSupport", "LoadLine"],
    dirichlet_masks =[true, true, true])
P = TrialFESpace(Q ,[1.0 ,1.0 ,1.0])

```

thank you!