[Paraview] OSPRay textures and materials mapping

Tue May 22 14:10:21 EDT 2018

And here is a python schell script to make step 4 (create the lookuptable)
automatic.

apartment = FindSource("sample_apartment.obj")

vtklevel = apartment.GetClientSideObject()

lut = GetColorTransferFunction('MaterialIds')

arr = vtklevel.GetOutput().GetFieldData().GetAbstractArray(0)

lut.InterpretValuesAsCategories = 1

ll = []

for x in range(0, arr.GetNumberOfTuples()):

ll.append(str(x))

ll.append(arr.GetValue(x))

David E DeMarle
Kitware, Inc.
Principal Engineer
21 Corporate Drive
Clifton Park, NY 12065-8662
Phone: 518-881-4909

On Tue, May 22, 2018 at 1:51 PM, David E DeMarle <dave.demarle at kitware.com>
wrote:

> On Tue, May 22, 2018 at 12:34 PM, David E DeMarle <
> dave.demarle at kitware.com> wrote:
>
>>
>> On Tue, May 22, 2018 at 10:34 AM, Jonathan Borduas <
>> jonathan.borduas at caboma.com> wrote:
>>
>>> Hi David,
>>>
>>> I was able to complete all the steps. As you probably know, the step
>>> four was tedious.
>>>
>>> However I couldn’t get the result I wanted since I couldn’t assign the
>>> right textures to the right areas. Is there a mechanism to assign the
>>> texture just like we assign materials ?
>>> I guess this is what you mean by “multi-texture isn’t implemented yet”.
>>> I could probably extract all objects using a connectivity filter and then
>>> manually assign the textures, but again it is a tedious process for complex
>>> objects.
>>>
>>>
>> Better to do it in the code. We read in all of the texture coordinates
>> when we read the .obj and all of the texture files when we read the .mtl ->
>> we just aren't using the right set of texture coordinates in all cases yet.
>> That is most of what I mean by multitexture.
>>
>> Is there a roadmap as to when the multi-texture could be implemented ?
>>>
>>
>> I'm hoping for 5.6 in a couple of months time. Although this is important
>> it may very well slip because of other priorities.
>>
>>
>
> In the meantime, this python programmable filter is a workaround.
>
> pdi = self.GetInput()
>
> pdo = self.GetOutput()
>
> pdo.ShallowCopy(pdi)
>
>
> arraynames = []
>
> arrays = {}
>
> for a in range(0,pdi.GetPointData().GetNumberOfArrays()):
>
>   array = pdi.GetPointData().GetArray(a)
>
>   if array.GetNumberOfComponents() != 2:
>
>     continue
>
>   arrname = array.GetName()
>
>   pdo.GetPointData().RemoveArray(arrname)
>
>   arraynames.append(arrname)
>
>   arrays[arrname] = array
>
>
> tcoords = vtk.vtkFloatArray()
>
> tcoords.SetName("TCoords")
>
> tcoords.SetNumberOfComponents(2)
>
> pdo.GetPointData().SetTCoords(tcoords)
>
> # todo numpy this to make it 100x faster
>
> for p in range(0, pdi.GetNumberOfPoints()):
>
>   tcoord = [0,0]
>
>   for arrname in arrays:
>
>     candidate = arrays[arrname].GetTuple2(p)
>
>     if candidate[0] == -1 and candidate[1] == -1:
>
>       continue
>
>     tcoord = candidate
>
>   tcoords.InsertNextTuple2(tcoord[0],tcoord[1])
>
>
>
>
>
>> It would be great to have readers that can load
>>> texture/Geometry/Materials files such as .obj (.mtl and .png), .fbx and
>>> .dwg.
>>>
>>
>> Agreed.
>>
>>
>>> Best regards,
>>>
>>>
>>>
>>> Jonathan Borduas
>>>
>>>
>>>
>>> *From:* David E DeMarle <dave.demarle at kitware.com>
>>> *Sent:* Friday, May 18, 2018 10:58 AM
>>> *To:* Jonathan Borduas <jonathan.borduas at caboma.com>
>>> *Cc:* paraview at public.kitware.com
>>> *Subject:* Re: [Paraview] OSPRay textures and materials mapping
>>>
>>>
>>>
>>> Hi Jonathan.
>>>
>>>
>>>
>>> Yes you can do that.
>>>
>>>
>>>
>>> 1) File->Load OSPRay Materials, switch the file type from "OSPRay
>>> Material Files (*.json)"  to "Wavefront Material FIles (*.mtl)". That will
>>> let you load all of the materials and textures. They should all show up in
>>> the Material list.
>>>
>>>
>>>
>>> 2) The OSPRay Material selection (on Display section of Properties Tab
>>> advanced) will have all of the individual materials listed in it + a few
>>> others including "Value Indexed" which is all the way at the bottom. Choose
>>> that it means "use the categorical color lookup table to decide what
>>> material to use for each block and or polygon"
>>>
>>>
>>>
>>> 3) Now change the scalar array to color by to "Material Id", a cell
>>> aligned array which has the material index to use for each cell.
>>>
>>>
>>>
>>> 4) Make up a categorical lookup table.
>>>
>>>    open spreadsheet view, switch to Field Data, look at the Material
>>> Names.
>>>
>>>    open the color map editor for the "Material Id", click on Interpret
>>> Values As Categories and the color will change from bluewhitered to
>>> extremely YELLOW.
>>>
>>>    add annotations, value 0 should be the name of the first entry in the
>>> Material Names array.
>>>
>>>
>>>
>>> Notes:
>>>
>>> * I have the trivial script somewhere that I used for the SC17 demo that
>>> makes up the lookup table for you. I'll try and dig that up.
>>>
>>> * in general it isn't a 1:1 match between mtl and ospray, in particular
>>> multitextures are not yet implemented
>>>
>>> * along those lines, the mtl parser I whipped up
>>> $PVSRC/VTK/Rendering/OSPRay/vtkMaterialLibrary::InternalParseMTL
>>> recognizes a "type" extension outside of mtl that lets you bring in
>>> ospray's nice materials instead of the default OBJMaterial. Glass and Metal
>>> are particularly nice.
>>>
>>>
>>>
>>> At some point I'll get around to making this all automatic. Patches are
>>> welcome in the meantime.
>>>
>>>
>>>
>>> good luck
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> David E DeMarle
>>> Kitware, Inc.
>>> Principal Engineer
>>> 21 Corporate Drive
>>> <https://maps.google.com/?q=21+Corporate+Drive+%0D%0AClifton+Park,+NY+12065&entry=gmail&source=g>
>>> Clifton Park, NY 12065-8662
>>> Phone: 518-881-4909
>>>
>>>
>>>
>>> On Fri, May 18, 2018 at 10:25 AM, Jonathan Borduas <
>>> jonathan.borduas at caboma.com> wrote:
>>>
>>> Hi,
>>>
>>> I tried rendering an .obj file running OSPRay that was exported from
>>> PCon Planner Version 7.7 Patch 1. The original file is a .dwg
>>>
>>>
>>>
>>> I used the PathThracer mode. However, attached to the .obj there is an
>>> .mtl file containing 50+ materials and 50+ texture (.png) files.
>>>
>>> I didn’t find an automated way to map all polydata of the .obj with
>>> their respective material and texture file and rendering them using OSPRay.
>>>
>>> It seems that I have to assign the material and texture to each polydata
>>> one-by-one.
>>>
>>>
>>>
>>> Is there a feature that will automatically map the respective textures
>>> and materials ?
>>>
>>> Here is the link to download the original .dwg file.
>>> https://www.easterngraphics.com/pcon/en/wp-content/uploads/2
>>> 015/03/sample_apartment.dwg
>>>
>>> You will need to export it to .obj using PCon Planner Version 7.7 Patch
>>> 1 with the File/Export/Geometry menu.
>>> I couldn’t share the .obj  file since the size is 60mb+
>>>
>>>
>>>
>>> Thank you
>>>
>>>
>>>
>>> Jonathan Borduas
>>>
>>>
>>>
>>>
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>>>
>>
>>
>
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