Different yarn can have the same gauge, which means they are just as thick or thin, and gives exactly the same amount of stitches in width and rows in height.
Yarn with the same gauge can be used on the same pattern.
Yarn with the same gauge, may have different yardage due to different weight of the fiber. When using an alterntive yarn, it's important to calculate the yardage needed.
Original pattern is using 500 g Alpaca. 500 g = 10 skeins.
Each Alpaca skein has 182 yards, so 1820 yards are needed for this pattern.
Let's use alternative yarn Cotton Viscose, which has 120 yds per skein.
1820 divided by 120 = 15.17. If using Cotton Viscose you will need 16 skeins.
Pattern DROPS 110-8 uses DROPS Alpaca. Here is a list over alternative yarns for this quality:
2 strands from yarn group A will create approx the same knitting gauge/tension as 1 strand from yarn group C.
Example 1: A garment is knitted in 2 strands Alpaca. The pattern calls for 6 balls of each colour. Firstly you need to establish how many meters of yarn is needed, i.e. 6 balls times the yardage of Alpaca, which is 167 meters, 6 x 167 meters = 1002 meters. If you wish to knit the garment in 1 strand Nepal, take these 1002 meters and divide by the yardage of Nepal (75 meters per ball). I.e. 1002 divided by 75 = 13.36, i.e. you need 14 balls of Nepal to knit the same garment in 1 strand.
Example 2: A garment is knitted in 1 strand Safran and 1 strand Cotton Viscose. The pattern calls for 4 balls Safran (160 meters per ball) and 6 balls Cotton Viscose (110 meters per ball). i.e. 4 x 160 meters = 640 meters Safran and 6 x 110 meters = 660 meters Cotton Viscose. If you wish to knit the garment in 1 strand Paris, take the lowest number, i.e. 640 meters and divide it by the yardage for Paris (75 meters per ball). I.e. 640 divided by 75 = 8.5, i.e. you need 9 balls of Paris to knit the garment in 1 strand.