Photogrammetry (YAY) and questions!

n4uj

Hey everybody!

Few days ago I read a very nice free tutorial made by @Sebvhe and this weekend I decided to give it a try!

The first two times I tried this technique, they were a complete fail, so I'm not going to post those... so yep, I lied in the thread title, THIS IS MY THIRD TIME.

This is such an interesting method and you can achieve really good looking results!
What I have found more unefficient is that it takes so long to get the high poly mesh with the dense texture on it. Until you reach that point, your computer is pretty useless, because there are no resources left for keep working on other stuff. So I recommend everybody to batch the process during night or working hours.
Another thing I have found during my short research is that if you are taking outdoors pictures, it is better to avoid low-angle shots. Normally you will take the shoots when the sky is cloudy, but if you make low-angle shots, and some of this kind of sky appears in your frame, it is most likelly that you are going to have a lot of contrast and the light meter of your camera is going to go crazy. AS a results the exposure in your photos can vary too much.
I didn't took any low angle shots for this practise because of this reason.
The low poly model was retopologized manually in maya from a mid poly. It has around 1500 tris.

By the way, what do you guys do with all the raws and tiffs after you finish a model? do you get rid of them? because they take a lot of space!




I have taken pictures of some other trees, but I will do them later this weekend
What do you think guys about this one ^^?

Best regards,

n4uj.

Sebvhe

n4uj said:

What I have found more unefficient is that it takes so long to get the high poly mesh with the dense texture on it. Until you reach that point, your computer is pretty useless, because there are no resources left for keep working on other stuff. So I recommend everybody to batch the process during night or working hours.

I usually process during working hours. When building the dense cloud you can use the gpu to process it and it makes it a million times faster. It only works for the dense cloud though.

n4uj said:

Another thing I have found during my short research is that if you are taking outdoors pictures, it is better to avoid low-angle shots. Normally you will take the shoots when the sky is cloudy, but if you make low-angle shots, and some of this kind of sky appears in your frame, it is most likelly that you are going to have a lot of contrast and the light meter of your camera is going to go crazy. AS a results the exposure in your photos can vary too much.
I didn't took any low angle shots for this practise because of this reason.

This shouldn't be an issue. If your shooting 100% manual, and you make sure the object is well exposed having low angles with the sky in the picture isn't an issue. Of course all the sky will be full white, but as long as the exposure is correct on your object (and the white of the sky doesn't leak too much, keep your lens clean) you will get a correct shot. Point is the exposure in your shot can vary a lot, but as long as the exposure on the part where your object is in the photo is correct, you're good. Doesn't matter if the background is burned or completely black.

n4uj said:

By the way, what do you guys do with all the raws and tiffs after you finish a model? do you get rid of them? because they take a lot of space!

I get rid or them when my model is done

n4uj said:

 

What do you think guys about this one ^^?

This is honestly pretty good. It's quiet funny, it seems that the very first good looking photogrammetry prop everyone did (me included) is a tree trunk. It's so easy to get very good results with these.
I'm actually surprised the grass did not turn out to be a blurry mess.
My only feedback would be to probably try tweaking the specular a bit. It currently makes the bark a little bit too even in terms of specular response, especially when you get some lichen or moss

Keep up that good job  

John Baxter

Looks really good. Since tree trunks are so easy to do, I'm wondering if anyone has a good workflow for doing an entire tree. Obviously twigs, branches, and leaves are a huge problem to scan, but would it be possible to scan the trunk and the main branches, then fill in the rest with more traditional methods?

Sebvhe

John Baxter said:

Would it be possible to scan the trunk and the main branches, then fill in the rest with more traditional methods?

I assume so, however I would work otherwise. I never tried it so I might be wrong. I would try to scan some leaves, I have seen a few on the internet so I guess it's not impossible to do. Then I would scan the trunk and also extract a tiling bark out of it. And use SpeedTree or similar to build the branches.

You actually made me want to try !

n4uj

John Baxter said:

Looks really good. Since tree trunks are so easy to do, I'm wondering if anyone has a good workflow for doing an entire tree. Obviously twigs, branches, and leaves are a huge problem to scan, but would it be possible to scan the trunk and the main branches, then fill in the rest with more traditional methods?

I have been thinking about this a few times. The main problem about trees is that they are much higher than you, so you cannot really take pictures from above and from the sides of the canopy, just from underneath, and that is not going to be enough. So photogrammetry there cannot help.
However what I think it could work is taking pictures of more than just the roots, depending on the heigh of the tree of course. Divide the tree in 3 parts: roots, tileable trunk and canopy and then make the branches as @Sebve said above.
I haven't try to scan any leaves myself, however I think it would be faster to build the 3d model, because modeling some leaves is very quick and you don't need a high detail on them.

n4uj

model

I just did another prop any cc is very welcomed!