Heat distortion works great for Star Destroyer exhaust!

jrsmoots Website User Posts: 3

I put together a little Star Wars fan art vfx shot this past weekend. Heat distortion worked great for simulating Star Destroyer exhaust.

I added the heat distortion to a 3d grade layer, placed it behind the destroyer model, then parened the grade layer to the destroyer.

I did have some trouble with glitchy shimmering of the shadowing on the Star Destroyer. I tried turning up Self Shadow Bias on the models material, which, at around 30 % fixed the shadows, but then caused whole large sections of the model to flash brightly. Couldn't find a workaround. Oh well.

Sort of related: Does anyone know a way to reduce the shimmering that occurs when 3d models are placed a large distance from camera? Small detail seems to cause problems. I know this is not unique problem for Hitfilm - I see same issue in Blender and Carrara.


  • rgbii
    rgbii Website User Posts: 965 Just Starting Out
    edited December 2014

    I'm not a 3D model expert, but I have noticed funny behavior dealing with shadows too.   While in the editor, the shadows are big and blocky, but I just assumed that was to speed up editing. However, once rendered they do the "glitchy shimmering" thing you mentioned. If you change the light(s) 'Shadow Color' to something like red, which is easier to see, it's very strange.

  • StormyKnight
    StormyKnight Moderator, Website User, Ambassador, Imerge Beta Tester, HitFilm Beta Tester Posts: 2,729 Ambassador

    Aside from the shimmering- looks really good! Such a simple way to do exhaust. I swear that Star Destroyer was going to hit the ground!  ;^)

  • Triem23
    Triem23 Moderator Moderator, Website User, Ambassador, Imerge Beta Tester, HitFilm Beta Tester Posts: 19,571 Ambassador

    Two possible things. 

    First,shadow maps get rasterized--with blocky shadows, you're close enough to see individual shadow pixels. Solution: scale everything  up.

    Second, I have a few models that shimmer. When I take these models into Blender, I find bad geometry and topology. In other words, a lot of free models are built wrong. If that Star Destroyer model is the one I think it is, it's got geometry issues. 

  • jrsmoots
    jrsmoots Website User Posts: 3

    Thanks for input, folks!!

  • darthmark
    darthmark Website User Posts: 18 Just Starting Out*

    Where did you get your star destroyer model? I am having a hard time finding one that looks good once imported.

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