Merge pull request #106 from ModiaSim/improve_cut_joint_message

Improve corner cases and error messages

Author: MartinOtter

src/Composition/dynamics.jl

@@ -12,10 +12,10 @@ function getJointsAndForceElementsAndObject3DsWithoutParents!(evaluatedParameter
                 if typeof(value.feature) <: Scene
                     push!(object3DWithoutParents, value)
                 else
-                    error("\n", value.path, " is an Object3D that has no parent, but no feature=Scene(..)!\n")
+                    error("\n", value.path, " is an Object3D that has no parent, but no feature=Scene(..)!\nThis means no Scene is defined (exactly one Object3D must have feature=Scene(..))!")
                 end
             elseif typeof(value.feature) <: Scene
-                error("\n", value.path, " is an Object3D that has feature=Scene(..) and has a parent (= ", value.parent.path, ")!\n")
+                error("\n", value.path, " is an Object3D that has feature=Scene(..) and has a parent (= ", value.parent.path, ")!\nThe Object3D with feature=Scene(..) is not allowed to have a parent!")
             end
 
         elseif typeof(value) <: Modia3D.Composition.Revolute 

src/Composition/joints/Fix.jl

@@ -34,11 +34,7 @@ struct Fix{F <: Modia3D.VarFloatType}
                 translation::AbstractVector = Modia3D.ZeroVector3D(F),
                 rotation::AbstractVector    = Modia3D.ZeroVector3D(F)) where F <: Modia3D.VarFloatType
 
-        (parent, child, cutJoint) = attach(obj1, obj2)
-        if cutJoint
-        error("\nError from Fix joint connecting ", Modia3D.fullName(obj1), " with ", Modia3D.fullName(obj2), ":",
-            "\nThis joint is a cut-joint which is not allowed.")
-        end
+        (parent, child, cutJoint) = attach(obj1, obj2, name = "Fix joint")  # an error is triggered if cutJoint=true
 
         r_rel = Modia3D.convertAndStripUnit(SVector{3,F}, u"m", translation)
         rot   = Modia3D.convertAndStripUnit(SVector{3,F}, u"rad", rotation)

src/Composition/joints/Prismatic.jl

@@ -16,7 +16,7 @@ get_eAxis(::Type{F}, axis::Int) where F <: Modia3D.VarFloatType = axis==  1 ? SV
                        error("Modia3D.Composition.Prismatic: axis = ", axis, " but must be 1, 2, 3, -1, -2, or -3.")
 
 """
-    joint = Prismatic(; obj1, obj2, path="", axis=1, s=0, v=0, canCollide=true)
+    joint = Prismatic(; obj1, obj2, axis=1, s=0, v=0, canCollide=true)
 
 Return a `joint` that translates `obj2::`[`Object3D`](@ref) with respect to
 `obj1::`[`Object3D`](@ref) along coordinate axis `axis` (`axis = 1,2,3,-1,-2,-3`)
@@ -52,11 +52,7 @@ mutable struct Prismatic{F <: Modia3D.VarFloatType} <: Modia3D.AbstractJoint
                          v::Real   = F(0.0),
                          canCollide::Bool = true) where F <: Modia3D.VarFloatType
 
-        (parent,obj,cutJoint) = attach(obj1, obj2)
-        if cutJoint
-            error("\nError from Prismatic joint connecting ", Modia3D.fullName(obj1), " with ", Modia3D.fullName(obj2), ":\n",
-                "    This joint is a cut-joint which is currently not supported.!")
-        end
+        (parent,obj,cutJoint) = attach(obj1, obj2, name = "Prismatic joint")  # an error is triggered if cutJoint=true
 
         if !(1 <= abs(axis) <= 3)
             error("\nError from Prismatic joint connecting ", Modia3D.fullName(obj1), " with ", Modia3D.fullName(obj2), ":\n",

src/Composition/joints/Revolute.jl

@@ -8,7 +8,7 @@ import Modia3D.Frames
 
 
 """
-    joint = Revolute(;obj1, obj2, path="", axis=3, phi=0, w=0, canCollide=false)
+    joint = Revolute(;obj1, obj2, axis=3, phi=0, w=0, canCollide=false)
 
 Return a Revolute `joint` that rotates `obj1::`[`Object3D`](@ref) into
 `obj2::`[`Object3D`](@ref) along the axis `axis` of `obj1` (`axis = 1,2,3,-1,-2,-3`).
@@ -43,11 +43,7 @@ mutable struct Revolute{F <: Modia3D.VarFloatType} <: Modia3D.AbstractJoint
                         w::Real   = F(0.0),
                         canCollide::Bool = false) where F <: Modia3D.VarFloatType
 
-        (parent,obj,cutJoint) = attach(obj1, obj2)
-        if cutJoint
-            error("\nError from Revolute joint connecting ", Modia3D.fullName(obj1), " with ", Modia3D.fullName(obj2), ":\n",
-                "    This joint is a cut-joint which is currently not supported.!")
-        end
+        (parent,obj,cutJoint) = attach(obj1, obj2, name = "Revolute joint")  # an error is triggered if cutJoint=true
 
         if !(1 <= abs(axis) <= 3)
             error("\nError from Revolute joint connecting ", Modia3D.fullName(obj1), " with ", Modia3D.fullName(obj2), ":\n",

src/Composition/joints/joints.jl

@@ -120,6 +120,8 @@ function attachAndReverseParents(newParent::Object3D{F}, obj::Object3D{F})::Noth
 end
 
 
+getParents(obj,rootPath) = "\"" * Modia3D.fullName(obj) * "\" has " * (length(rootPath) == 0 ? "no parents" : "parents: $rootPath")
+
 """
     (obj1, obj2, cutJoint) = attach(frame_a, frame_b)
 
@@ -128,7 +130,7 @@ and cutJoint = false is returned.
 
 If they have the same root, the tree is not modified and cutJoint=true is returned.
 """
-function attach(obj1::Object3D, obj2::Object3D)
+function attach(obj1::Object3D, obj2::Object3D; name = "")
    root1 = rootObject3D(obj1)
    root2 = rootObject3D(obj2)
    #println("attach: obj1 = ", Modia3D.fullName(obj1), ", root = ", Modia3D.fullName(root1))
@@ -137,6 +139,16 @@ function attach(obj1::Object3D, obj2::Object3D)
    if root1 ≡ root2
       # Compute absolute positions
       # updatePosition!(root1)
+
+      if name != ""
+        # Collect all objects that form a loop
+        rootPath1 = rootObject3DPath(obj1)
+        rootPath2 = rootObject3DPath(obj2)
+        error("\nError from $name connecting \"", Modia3D.fullName(obj1), "\" with \"", Modia3D.fullName(obj2), "\":\n",
+                "    ", getParents(obj1,rootPath1), "\n",
+                "    ", getParents(obj2,rootPath2), "\n",
+                "    Therefore, a closed kinematic loop is defined, which is currently not supported.")
+      end     
       return (obj1,obj2,true)
    end
 

src/Composition/joints/object3DMotion.jl

@@ -14,7 +14,7 @@ end
 
 
 """
-    joint = FreeMotion(; obj1, obj2, path="", r, rot, v, w)
+    joint = FreeMotion(; obj1, obj2, r, rot, v, w)
 
 Return a `joint` that describes the free movement of `obj2::`[`Object3D`](@ref)
 with respect to `obj1::`[`Object3D`](@ref). The initial position is `r`

src/Composition/massPropertiesComputation.jl

@@ -104,7 +104,7 @@ function addOrSubtractMassPropertiesOfChildToRoot!(obj_root::Object3D{F}, obj_ch
         m = m_root + m_child
 
         # common center of mass (parent + child)
-        @assert(m > 0.0)
+        @assert(m >= 0.0)
         rCM = (m_root * rCM_root + m_child * rCM_child_new)/m
 
         # I: substract new common mass multiplied with skew matrices of

src/Composition/object3D.jl

@@ -551,6 +551,18 @@ function rootObject3D(obj::Object3D{F}) where F <: Modia3D.VarFloatType
 end
 
 
+"""    path = rootObject3DPath(obj) - returns a vector of Object3D names of all objects from obj to root"""
+function rootObject3DPath(obj::Object3D{F}) where F <: Modia3D.VarFloatType
+    path = String[]
+    obj1 = obj
+    while hasParent(obj1)
+        obj1 = obj1.parent
+        push!(path, obj1.path)
+    end
+    return path
+end
+
+
 """    removeChild!(obj, child) - Remove child from obj.children"""
 function removeChild!(obj::Object3D{F}, child::Object3D{F})::Nothing where F <: Modia3D.VarFloatType
     children = obj.children

src/ModiaInterface/buildModia3D.jl

@@ -97,6 +97,8 @@ function buildModia3D!(model::AbstractDict, FloatType::Type, TimeType::Type,
     jointStatesFreeMotion_isrot123 = Expr[]
     freeMotionIndices              = OrderedCollections.OrderedDict{String,Int}()
 
+    println("modelPath = $modelPath")
+    
     modelPathAsString = isnothing(modelPath) ? "" : string(modelPath)
 
     i=1
@@ -243,6 +245,9 @@ function buildModia3D!(model::AbstractDict, FloatType::Type, TimeType::Type,
         else
             @error "Error should not occur (buildOption = $buildOption)"
         end
+    else
+        # ndofTotal == 0
+        mbsCode = mbs_variables | Model(equations = :[$(mbs_equations...)])
     end
 
     # Store info in buildDict

src/Shapes/massProperties.jl

@@ -15,7 +15,7 @@ struct MassProperties{F <: Modia3D.VarFloatType} <: Modia3D.AbstractMassProperti
     #---------------- different constructors for MassProperties -----------------
     # Constructor 0: takes mass, centerOfMass and inertiaMatrix as input values
     function MassProperties{F}(mass::Number, centerOfMass::AbstractVector, inertiaMatrix::AbstractMatrix) where F <: Modia3D.VarFloatType
-        @assert(mass > 0.0)
+        @assert(mass >= 0.0)
         new(mass, centerOfMass, inertiaMatrix)
     end
 end