Please help!!! NEW PROBLEM

  • Thread starter Boffin
  • 16 comments
  • 1,281 views
Boffin

Boffin

4,555
Australia
Australia
Hi guys and girls

I am trying to do a shot where there is a lot of motion blur with a clean car (you know the sort).

I spiced up the colours, got the car real nice, but when it's time for the addtition of motion blur, how do I get it so nothing but the car is clean?

Let me put it this way.
What I am doing is cutting the car out (so theres a hole where you can see the trasparent layer) and adding motion blur, then putting the car back.

My problem is that when I add the motion blur, the hole gets blurred so I have an out-of-shape hole with sides that are semi trasparent.
How do I just get a clean cut hole with the road around it blurred?
I tried looking at the tutorials but it was no use.
Any help would be good.

Another thing is after you've finished replacing a section of the image (removed to change colour) how can you deselect it?

Any help for this would be awesome

thanks
 
Last edited:
I haven't messed around with gimp for quite a while but I have an idea. What about possibly taking and cutting the car out, creating a layer for it, setting that aside, create another layer, and duplicating the background with the hole cut in it. Then you could blur one background layer, and have the other having a perfect outline like you want so you can match the car back to the original place.

And if that makes sense. I suggest doing it.
 
ok..I'll give it a shot

another thing, its all very well making a layer...but in GIMP, apart from actually on the image (and this goes back to not being able to deselect), how can one manage layers? is there a dedicated window like in PS?
 
Which version of gimp do you use? On most, there's a bar at the top. Go to dialogs, and open the layers dialog. Then for the motion blur. I had that exact same problem. Duplicate the original background layer. Then cut out the car from the duplicate layer. Duplicate the copy about 15 times. Apply the motion blur at whatever length you want to the highest placed bg layer copy. So as an example, if you apply a motion blur with the length of 30. On the next one down, apply one of say 25, then 22, then 19, etc etc. Gradually make the blur shorter and shorter. PM me if this doesn't make sense. I can take screenshots for you to better explain if you want.
 
Sorry for the double post...it's so people can flag it down.

How I did the shot...

Ok, cut the car out(with lassoo tool) - copying to a new layer - making sure that what left behind is the chequered transparent background - not the white background,. If you want to add noise to the road, highlight the road (with lassoo tool) and fiddle with the noise. When you are happy, copy this layer 3 more times.

PROBLEM - WHEN YOU COPY THE LAYER TO A NEW WINDOW THE CHEQUERED SECTION TURNS WHITE.
How to fix this is to copy the original layer (with the white bit), then delete the new copied layer - now the layer should turn chequered insteadof white, and now go back to the original, copy it and paste in new layer. YOU HAVE TO RE PRESS "COPY" OTHER WISE IT GOES WHITE AGAIN.
Repeat the process untill you get four layers.

Then on one layer, figure out where you want the point of the blur, and when finalised, write it down somewhere so you remember.
Now play with the blur length untill you are happy - this will be the layer that everybody sees. Make sure the BLUR OUTWARDS box is ticked.
Then press ok and wait untill it's done.

PROBLEM - IT"S MOTIONED BLURED THE HOLE WHERE THE CAR USED TO BE AND NOW I HAVE A SEMI TRANSPARENT HOLE THATS BIGGER THAN THE CAR!
This is why we have the 3 extra layers.
On one of the layers, put the blur the same length as the first layer, only this time the box BLUR OUTWARDS should be unticked.
If you can work it out, the blur will now blur the hole the other way...and when the two are stacked, you should be left with a hole smaller than your car. For the last two layers, one should be blurred in, and one out but this time make the blurr smaller (like half the first blur). This is to help you re position your car properly.

Now, as GIMP doesn't have an advanced layer tool, you have to stack the layers in order from bottom to top.

The order is.

Short blurred in
Short out
Long in
Long out

Please note that you have to copy all the layers onto the short IN layer because thats the bottom layer

any problems?
PM or post here

Ohh and another thing..if you want to deselect something in GIMP - Anchor layer 👍
 
Last edited:
Is this using Zoom blur? You say write down co-ordinates so I'm presuming so. Thanks for the instructions though, I was just starting a 15 layer motion blur with a white background. You saved me alot of time!
 
Download 2.4. :D It's soooo much easier. When 2.6 came out, I tried it, but it was sooo terrible that I gave up and went back to 2.4.
 
OK, New problem!!

I've mastered the zoom blur which I was having trouble with, but now my problem is:

How do I do zoom blur when the focus (or centre of the zoom) is out of the picture.
I'm using GIMP, but I tried it on my bro's PS CS4 with no more success. Do I have to manually blur everything in a straight line?

Thanks in advance

👍 :)
 
I don't know but, you might try this, sounds crazy, but it might work. Enlarge the car, or reduce the size of the background, every so slightly, so the edges of cut out car, just barely overlap and cover the unwanted edge of the background. I think you're looking for a more professional technique than that but, hey it's simple, and it might work.
 

Latest Posts

Back