I am using Blender 2.77 and want to render many smoke simulations in cycles from a script. The idea is to take one template smoke simulation, change the parameters as specified in a csv table, render with the changed parameters and then move on to the line in the csv table. Whenever I run my script, the rendered output of the smoke simulation is the same although the parameters are changed in the blend file. I suspect that I need to rerun the smoke simulation each time I want to render, but I am not sure how to do that.

# for each line in csv file do this
for k in range(len(outputName)):

# skip first line
if k == 0:
    print (" skip header")
    # change smoke settings according to csv file

    # get the attributes from the Camera, Flow and Domain object
    myFlow   = bpy.data.objects["Circle"].modifiers["Smoke"].flow_settings
    myDomain = bpy.data.objects["Smoke Domain"].modifiers["Smoke"].domain_settings

    # get the domain and flow attributes
    smokeVorticity  = myDomain.vorticity  # amount of turbulence
    smokeAlpha      = myDomain.alpha
    smokeDensity    = myFlow.density
    smokeTempDiff   = myFlow.temperature                

    # set domain and flow attributes
    smokeVorticity     = vorticity[k]
    smokeAlpha          = alpha[k]
    smokeDensity        = density[k]

    # set windforce
    bpy.data.objects["Field"].field.strength = float(force[k])

    # set render output settings
    bpy.data.scenes["Smoke"].cycles.seed = int(seed[k])

    # set number of samples to render each pixel (the more the longer it takes)
    bpy.data.scenes["Smoke"].cycles.samples = 3  #crank this up to at least 300

    # set end frame
    bpy.data.scenes["Smoke"].frame_end = 50  # change this to 100 later

    # set render path: 
    fileName = bpy.path.basename(bpy.context.blend_data.filepath)
    fileName = os.path.splitext(fileName)[0]
    bpy.data.scenes["Smoke"].render.filepath = os.path.join("//renderings", "smoke", outputName[k], outputName[k] + "_" )

    # render the scene
    bpy.ops.render.render(animation =True)
    print(outputName[k] + " rendered, moving on to next file")
  • $\begingroup$ I realized that I did not free the cache and baked for each render. So I added that piece of code:<br/> <br/> # free bake cache<br/> bpy.ops.ptcache.free_bake_all()<br/> # bake the smoke simulation<br/> bpy.ops.ptcache.bake_all(bake = True)<br/> <br/> However, that still does not solve the problem, and when I run my script, I am still getting empty frames. <br/> Here is a link to the blend file: <br/>[link]dropbox.com/s/gtkmx8d98i2gcu4/… [link] $\endgroup$ – makinate Nov 18 '16 at 19:43

I figured it out; I needed to free the bake cache before baking:

    # free bake cache

    # bake the smoke simulation
    bpy.ops.ptcache.bake_all(bake = True)
  • $\begingroup$ this did not solve the issue. Anyone? $\endgroup$ – makinate Nov 18 '16 at 19:51

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.