If you can see the Terraformign resources, you already HAVE the Terraforming tech. Terestial Sculpting is what unlocks both (basic) Terraforming and the Resources to make Terraforming cheaper.
I jsut looked at the files. Apparently the wieght is divided by 3 if you lack a New Worlds specialist.
tech_terrestrial_sculpting = {
cost = @tier1cost3
area = society
tier = 1
category = { new_worlds }
prerequisites = { "tech_colonization_1" }
weight = @tier1weight3
feature_flags = {
build_terraform_station
}
weight_modifier = {
modifier = {
factor = 0.33
NOT = {
research_leader = {
area = society
has_trait = "leader_trait_expertise_new_worlds"
}
}
}
modifier = {
factor = 0
NOT = { has_country_flag = homesystem_surveyed }
is_ai = no
}
}
ai_weight = {
modifier = {
factor = 1.25
research_leader = {
area = society
has_trait = "leader_trait_expertise_new_worlds"
}
}
}
}