Examples - Surfaces

- A wide range of Surface types are available in FRED. Each surface has Aperture, Location/Orientation, Material, Coating, Raytrace control, Scatter, Glue, Grating, Trimming volume, Visualization and Auxiliary data components.

- Surfaces MUST be added in the Tree under a Custom Element. Failure to do so could lead to erroneous behavior.

- All surfaces require a T_ENTITY structure as part of their definition in order to specify a minimum amount of information such as parentage, name, trace status and basic visualization attributes. An un-initialized T_ENTITY structure will often lead to undesirable surface attributes. Initializing the T_ENTITY structure and providing a unique name is always recommended.

- Upon creation, all surfaces acquire default Trimming, Location/Orientation, Visualization, Material, Coating, and Raytrace control attributes shown below. Unless specified, FRED will also give the new surface the name "Surf n" where n is an automatically incremented integer. The user is responsible for supplying explicit values for these attributes to achieve the desired result.

Attribute	Default
Trimming	XYZ semi-apertures = 1, cylindrical
Location/Orientation	entity's local coordinate system
Visualization	Flat shading, shine=28, opacity=1, local coordinate axes lengths +/- 1.2
Material	material 1=Air, material 2=Air
Coating	Absorb (100%)
Raytrace Control	Halt All
Name	Surf n (n is an auto-incremented integer)

- There need not be a separate T_ENTITY structure for each new surface. Once declared, a T_ENTITY structure can be reused as often as necessary as long as the desired attributes are updated for each instance of its use.

"Add" a Surface or Surface attribute

As a minimum, a T_ENTITY structure must be declared when creating new surfaces. Always initialize this structure to insure predictable results. In the following example, a single T_ENTITY structure is used to create a series of different surfaces. Note that the same structure can be utilized in the creation of the Custom Elements under which these surface reside.

Please make sure that your script is followed by an Update command so that your geometry is properly created on the object tree. Failure to do so will leave the document in an invalid state and may need to be re-loaded.

Adding a Plane or Conic

Dim ent As T_ENTITY
InitEntity ent

ent.parent=2
ent.name="First element"
c1id = AddCustomElement ( ent )

ent.parent=c1id
ent.name="Plane 1.1"
p1id = AddPlane ( ent )

ent.name="conic 1.1"
con1id = AddConic ( ent, 0.2, -1 )
'*******************************

Adding a Tube

ent.parent=2
ent.name="Second element"
c2id = AddCustomElement ( ent )

Dim et As T_TUBE
InitTube tb

ent.parent=c2id
ent.name="Tube 1.1"
'T_TUBE data goes here
t1id=AddTube ( ent, tb )
'*******************************

Adding a Conic Foci

ent.parent=2
ent.name="Third element"
c3id = AddCustomElement ( ent )

Dim cf As T_CONICFOCI
InitConicFoci cf

ent.parent=c3id
ent.name="confoc 1.1"
'T_CONICFOCI data goes here
cfid=AddConicFoci( ent, cf )
'*******************************

Adding an Asphere

ent.parent=2
ent.name="Fourth element"
c4id = AddCustomElement ( ent )

ent.parent=c4id
ent.name="asphere 1.1"

'user defined aspheric coefficients

Dim evena(2) As Double
Dim odda(2) As Double

evena(0)=1.32e-2: evena(1)=-4.923e-4: evena(2)=7.662e-7
odda(0)=-3.77e-3: odda(1)=4.88e-5: odda(2)=0

asp1id = AddAsphere( ent, 0.4, -2.038, evena, odda )
'*******************************

Adding a Polynomial Asphere

ent.parent=2
ent.name="Fifth element"
c5id = AddCustomElement ( ent )

ent.parent=c5id
ent.name="poly asphere 1.1"

'user defined aspheric coefficients

Dim coefp(4) As Double

coefp(0)=-1.2e-4: coefp(1)=2.89e-4: coefp(2)=0.4e-5: coefp(3)=6.6e-7: coefp(4)=9.3e-8

pa1id = AddPolynomialAsphere ( ent, -0.25, 1.6, coefp )

'*******************************

Adding a Toroidal Asphere

ent.parent=2
ent.name="Sixth element"
c6id = AddCustomElement ( ent )

Dim tasp As T_TOROIDALASPHERE
InitToroidalAsphere tasp

ent.parent=c6id
ent.name="toroidal asphere 1.1"

'T_TOROIDALASPHERE data goes here

'user defined toroidal asphere coefficients
Dim ctasp(1,3) As Double
ctasp(0,0)=0 : ctasp(1,0)=0 'unused placeholders - should be set to zero
ctasp(0,1)=0 : ctasp(1,1)=0 'unused placeholders - should be set to zero
'A coef B coef
ctasp(0,2)=0.03 : ctasp(1,2)=0.04
ctasp(0,3)=-0.0005 : ctasp(1,3)=-0.004

id = AddToroidalAsphere ( ent, tasp, ctasp )

'*******************************

Adding an XY Toroidal Asphere

ent.parent=2
ent.name="Seventh element"
c7id = AddCustomElement ( ent )

Dim xytasp As T_TOROIDALASPHERE
InitToroidalAsphere xytasp

ent.parent=c7id
ent.name="XYtoroidal asphere 1.1"

'T_TOROIDALASPHERE data goes here

'user defined XYtoroidal asphere coefficients
Dim cxytasp(1) As Double
cxytasp(0)=0.002 : cxytasp(1)=0.003

id = AddXYToroidalAsphere ( ent, xytasp, cxytasp )

'*******************************

Adding a Zernike Aspheric Surface

ent.parent=2
ent.name="Eigth element"
c8id = AddCustomElement ( ent )

ent.parent=c8id
ent.name="Zernike aspheric 1.1"

'use SetZernikeSurfCoefInterpretation, SetZernikeSurfBaseConic, SetZernikeSurfIthAsphCoef
'to set base conic, aspheric terms and coefficient interpretation

Dim zrn8(4) As Double
zrn8(0)=0.2 : zrn8(1)=0.3 : zrn8(2)=0.4 : zrn8(3)=0 :zrn8(4)=0.5 'Zernike coefficients

id = AddZernikeSurf ( ent, 2.5, 2.5, zrn8 )

'*******************************

Adding an Implicit Scripted Surface

ent.parent=2
ent.name="Ninth element"
c9id = AddCustomElement ( ent )

ent.parent=c9id
ent.name="Implicit Script Surface 1.1"

scrptsurfid=AddImplicitScriptSurf ( ent )

'use SetImplicitScript to specify script name

'*******************************

Adding a NURB Surface (using 1-D points array, see the AddNURBSurf topic for discussion)

ent.parent=2
ent.name="Tenth element"
c10id = AddCustomElement ( ent )

ent.parent=c10id
ent.name="NURBs Surface 1.1"

Dim knotU(3) As Double

Dim knotV(3) As Double

Dim Npoints(3*4-1) As Double

Dim Nweights(3) As Double

knotU(0)=0 : knotU(1)=0 : knotU(2)=1 : knotU(3)=1
knotV(0)=0 : knotV(1)=0 : knotV(2)=1 : knotV(3)=1
Npoints(0)=-0.5 : Npoints(1)=-0.5 : Npoints(2)=0 : Nweights(0)=1
Npoints(3)=0.5 : Npoints(4)=-0.5 : Npoints(5)=0 : Nweights(1)=1
Npoints(6)=-0.5 : Npoints(7)=0.5 : Npoints(8)=0 : Nweights(2)=1
Npoints(9)=0.5 : Npoints(10)=0.5 : Npoints(11)=0 : Nweights(3)=1

NURBid = AddNURBSurf ( ent, 1, 1, 2, 2, knotU, knotV, Npoints, Nweights )

'*******************************

Adding a Revolved Surface

ent.parent=2
ent.name="Eleventh element"
c11id = AddCustomElement ( ent )

ent.parent=c11id
ent.name="Revolved Surface 1.1"

Dim rvs As T_REVOLVESURF

InitRevolveSurf curvid, rvs 'uses existing curve to create surface of revolution

'T_REVOLVESURF data goes here

rsid = AddRevolveSurf ( ent, rvs )

'*******************************

Adding a Ruled Surface

ent.parent=2
ent.name="Twelveth element"
c12id = AddCustomElement ( ent )

ent.parent=c12id
ent.name="Ruled Surface 1.1"

Dim rlds As T_RULEDSURF 'no Init command exists for Ruled Surface so attributes MUST be assigned

rlds.curve1=curv1id

rlds.curve2=curv2id

rlds.crossConnect=True

rld1id = AddRuledSurf ( ent, rlds )

'*******************************

Adding a Spline Surface

ent.parent=2
ent.name="Thirteenth element"
c13id = AddCustomElement ( ent )

ent.parent=c13id
ent.name="Spline Surface 1.1"

Dim uBp(1) As Double
Dim vBp(1) As Double
Dim Spcoef(2,2,2,0,0) As Double

uBp(0)=0 : uBp5(1)=1
vBp(0)=0 : vBp(1)=1
Spcoef(0,0,0,0,0)=0 : Spcoef(1,0,0,0,0)=0 : Spcoef(2,0,0,0,0)=0
Spcoef(0,1,0,0,0)=0 : Spcoef(1,1,0,0,0)=1 : Spcoef(2,1,0,0,0)=0
Spcoef(0,2,0,0,0)=0 : Spcoef(1,2,0,0,0)=0 : Spcoef(2,2,0,0,0)=0
Spcoef(0,0,1,0,0)=1 : Spcoef(1,0,1,0,0)=0 : Spcoef(2,0,1,0,0)=0
Spcoef(0,1,1,0,0)=0 : Spcoef(1,1,1,0,0)=0 : Spcoef(2,1,1,0,0)=0
Spcoef(0,2,1,0,0)=0 : Spcoef(1,2,1,0,0)=0 : Spcoef(2,2,1,0,0)=0
Spcoef(0,0,2,0,0)=0 : Spcoef(1,0,2,0,0)=0 : Spcoef(2,0,2,0,0)=0
Spcoef(0,1,2,0,0)=0 : Spcoef(1,1,2,0,0)=0 : Spcoef(2,1,2,0,0)=0
Spcoef(0,2,2,0,0)=0 : Spcoef(1,2,2,0,0)=0 : Spcoef(2,2,2,0,0)=0

splnid = AddSplineSurf ( ent, 2, 2, uBp, vBp, Spcoef )

'*******************************

Adding a Tabulated Cylinder

ent.parent=2
ent.name="Fourteenth element"
c14id = AddCustomElement ( ent )

ent.parent=c14id
ent.name="Tabulated Cylinder 1.1"

Dim tc As T_TABULATEDCYLINDER 'no Init command exists for Tabulated Cylinder so attributes MUST be assigned

tc.x=0 : tc.y=0 : tc.z=1 'extrusion direction vector

tc.curve=crv8id 'identifier of curve to be extruded

tcylid = AddTabulatedCylinder ( ent, tc )

'*******************************

Adding a Trimmed Parametric Surface

ent.parent=2
ent.name="Fifteenth element"
c15id = AddCustomElement ( ent )

ent.parent=c15id
ent.name="Trimmed Parametric 1.1"

id = AddTrimmedParametric ( ent, 38, 26, 27 )

'*******************************

Update

"AuxData" management

"Delete" a Surface attribute

Delete a scatter model from a surface as shown in this example:

id=FindName("Diffuser")

scid=FindScatter("White Lambertian")

DeleteSurfIthScatter id, scid

"Init" a Surface structure

(see "Add" section above)

"Get/Set" Surface attributes

Use the "Get" and "Set" commands to retrieve and change Surface parameters. In this example, the 2nd to the last XYToroidal Aspheric coefficient is reduced by 10%:

id=FindName("potato chip optic")

n = GetXYToroidalAsphereCoefCount ( id )

cval = GetXYToroidalAsphereIthCoef ( id, n-3 )

cval=cval*0.9

SetXYToroidalAsphereIthCoef id, n-3, cval

In this example, the trimming hole location in a primary mirror is shifted in the +x-direction by 0.2 mm:

Dim tv As T_TRIMVOLUME

id=FindName("Primary")

GetTrimVolume id, tv

tv.xCenterHole=tv.xCenterHole+0.2

SetTrimVolume id, tv

Material, Scatter model, Coatings and Raytrace controls for a specific surface can be retrieved and changed. Here, all surfaces using a specific Raytrace control have that attribute changed:

For i=0 To GetEntityCount()-1
If IsSurface(i) Then
If GetSurfRaytraceCtrl(i)=FindRaytraceCtrl("Transmit Specular") Then
SetSurfRaytraceCtrl i, FindRaytraceCtrl("Allow All")
End If
End If
Next i